Chapter 6 The Link Layer and LANshomepage.ntu.edu.tw/~pollyhuang/teach/intro-cn... · §each...

Computer Networking A Top Down Approach

A note on the use of these Powerpoint slidesWersquore making these slides freely available to all (faculty students readers) Theyrsquore in PowerPoint form so you see the animations and can add modify and delete slides (including this one) and slide content to suit your needs They obviously represent a lot of work on our part In return for use we only ask the following

sect If you use these slides (eg in a class) that you mention their source (after all wersquod like people to use our book)

sect If you post any slides on a www site that you note that they are adapted from (or perhaps identical to) our slides and note our copyright of this material

Thanks and enjoy JFKKWR

All material copyright 1996-2016JF Kurose and KW Ross All Rights Reserved

7th Edition Global Edition Jim Kurose Keith RossPearsonApril 2016

Chapter 6The Link Layer and LANs

6-1Link Layer and LANs

Chapter 6 Link layer and LANsour goalssect understand principles behind link layer

servicesbull error detection correctionbull sharing a broadcast channel multiple accessbull link layer addressingbull local area networks Ethernet VLANs

sect instantiation implementation of various link layer technologies


Link layer LANs outline

61 introduction services62 error detection

correction 63 multiple access

protocols64 LANs

bull addressing ARPbull Ethernetbull switchesbull VLANS

65 link virtualization MPLS

66 data center networking

67 a day in the life of a web request


Link layer introductionterminologysect hosts and routers nodessect communication channels that

connect adjacent nodes along communication path linksbull wired linksbull wireless linksbull LANs

sect layer-2 packet frameencapsulates datagram

data-link layer has responsibility of transferring datagram from one node to physically adjacent node over a link


Link layer context

sect datagram transferred by different link protocols over different linksbull eg Ethernet on first link

frame relay on intermediate links 80211 on last link

sect each link protocol provides different servicesbull eg may or may not

provide rdt over link

transportation analogysect trip from Princeton to Lausanne

bull limo Princeton to JFKbull plane JFK to Genevabull train Geneva to Lausanne

sect tourist = datagramsect transport segment =

communication linksect transportation mode = link

layer protocolsect travel agent = routing

algorithm


Link layer servicessect framing link access

bull encapsulate datagram into frame adding header trailerbull channel access if shared mediumbull ldquoMACrdquo addresses used in frame headers to identify

source destination bull different from IP address

sect reliable delivery between adjacent nodesbull we learned how to do this already (chapter 3)bull seldom used on low bit-error link (fiber some twisted

pair)bull wireless links high error rates

bull Q why both link-level and end-end reliability


sect flow controlbull pacing between adjacent sending and receiving nodes

sect error detection bull errors caused by signal attenuation noise bull receiver detects presence of errors

bull signals sender for retransmission or drops frame

sect error correctionbull receiver identifies and corrects bit error(s) without resorting to

retransmission

sect half-duplex and full-duplexbull with half duplex nodes at both ends of link can transmit but not

at same time

Link layer services (more)


Where is the link layer implementedsect in each and every hostsect link layer implemented in ldquoadaptorrdquo (aka network interface card NIC) or on a chipbull Ethernet card 80211

card Ethernet chipsetbull implements link physical

layersect attaches into hostrsquos system

busessect combination of hardware

software firmware

controller

physicaltransmission

cpu memory

host bus (eg PCI)

network adaptercard

applicationtransportnetwork

link

linkphysical


Adaptors communicating

sect sending sidebull encapsulates datagram in

framebull adds error checking bits

rdt flow control etc

sect receiving sidebull looks for errors rdt

flow control etcbull extracts datagram passes

to upper layer at receiving side

controller controller

sending host receiving host

datagram datagram

datagram

frame





protocols64 LANs






Error detectionEDC= Error Detection and Correction bits (redundancy)D = Data protected by error checking may include header fields

bull Error detection not 100 reliablebull protocol may miss some errors but rarelybull larger EDC field yields better detection and correction

otherwise


Parity checking

single bit paritysect detect single bit

errors

two-dimensional bit paritysect detect and correct single bit errors

0 0


Check out the online interactive exercises for more examples httpgaiacsumassedukurose_rossinteractive

Internet checksum (review)

sendersect treat segment contents

as sequence of 16-bit integers

sect checksum addition (1rsquos complement sum) of segment contents

sect sender puts checksum value into UDP checksum field

receiversect compute checksum of

received segmentsect check if computed

checksum equals checksum field valuebull NO - error detectedbull YES - no error detected

But maybe errors nonetheless

goal detect ldquoerrorsrdquo (eg flipped bits) in transmitted packet (note used at transport layer only)


Cyclic redundancy checksect more powerful error-detection codingsect view data bits D as a binary numbersect choose r+1 bit pattern (generator) Gsect goal choose r CRC bits R such that

bull ltDRgt exactly divisible by G (modulo 2) bull receiver knows G divides ltDRgt by G If non-zero remainder

error detectedbull can detect all burst errors less than r+1 bits

sect widely used in practice (Ethernet 80211 WiFi ATM)


CRC example

wantD2r XOR R = nG

equivalentlyD2r = nG XOR R

equivalentlyif we divide D2r by G want remainder R to satisfy

R = remainder[ ]D2r

G



Quiz Time




protocols64 LANs






Multiple access links protocolstwo types of ldquolinksrdquosect point-to-point

bull PPP for dial-up accessbull point-to-point link between Ethernet switch host

sect broadcast (shared wire or medium)bull old-fashioned Ethernetbull upstream HFCbull 80211 wireless LAN

shared wire (eg cabled Ethernet)

shared RF(eg 80211 WiFi)

shared RF(satellite)

humans at acocktail party

(shared air acoustical)


Multiple access protocolssect single shared broadcast channel sect two or more simultaneous transmissions by nodes

interference bull collision if node receives two or more signals at the same

time

multiple access protocolsect distributed algorithm that determines how nodes share

channel ie determine when node can transmitsect communication about channel sharing must use channel itself

bull no out-of-band channel for coordination


An ideal multiple access protocol

given broadcast channel of rate R bpsdesiderata

1 when one node wants to transmit it can send at rate R2 when M nodes want to transmit each can send at average

rate RM3 fully decentralized

bull no special node to coordinate transmissionsbull no synchronization of clocks slots

4 simple


MAC protocols taxonomy

three broad classessect channel partitioning

bull divide channel into smaller ldquopiecesrdquo (time slots frequency code)bull allocate piece to node for exclusive use

sect random accessbull channel not divided allow collisionsbull ldquorecoverrdquo from collisions

sect ldquotaking turnsrdquobull nodes take turns but nodes with more to send can take longer

turns


Channel partitioning MAC protocols TDMA

TDMA time division multiple accesssect access to channel in rounds sect each station gets fixed length slot (length = packet

transmission time) in each round sect unused slots go idle sect example 6-station LAN 134 have packets to

send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe


FDMA frequency division multiple access sect channel spectrum divided into frequency bandssect each station assigned fixed frequency bandsect unused transmission time in frequency bands go idle sect example 6-station LAN 134 have packet to send frequency

bands 256 idle

frequ

ency

ban

ds

time

FDM cable

Channel partitioning MAC protocols FDMA


Quiz Time

Random access protocolssect when node has packet to send

bull transmit at full channel data rate Rbull no a priori coordination among nodes

sect two or more transmitting nodes ldquocollisionrdquosect random access MAC protocol specifies

bull how to detect collisionsbull how to recover from collisions (eg via delayed

retransmissions)sect examples of random access MAC protocols

bull slotted ALOHAbull ALOHAbull CSMA CSMACD CSMACA


Slotted ALOHA

assumptionssect all frames same sizesect time divided into equal size

slots (time to transmit 1 frame)

sect nodes start to transmit only at slot beginning

sect nodes are synchronizedsect if 2 or more nodes transmit

in slot all nodes detect collision

operationsect when node obtains fresh

frame transmits in next slotbull if no collision node can send

new frame in next slotbull if collision node retransmits

frame in each subsequent slot with prob p until success


Prossect single active node can

continuously transmit at full rate of channel

sect highly decentralized only slots in nodes need to be in sync

sect simple

Conssect collisions wasting slotssect idle slotssect nodes may be able to

detect collision in less than time to transmit packet

sect clock synchronization

Slotted ALOHA1 1 1 1

2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


sect suppose N nodes with many frames to send each transmits in slot with probability p

sect prob that given node has success in a slot = p(1-p)N-1

sect prob that any node has a success = Np(1-p)N-1

sect max efficiency find p that maximizes Np(1-p)N-1

sect for many nodes take limit of Np(1-p)N-1 as N goes to infinity givesmax efficiency = 1e = 37

efficiency long-run fraction of successful slots (many nodes all with many frames to send)

at best channelused for useful transmissions 37of time

Slotted ALOHA efficiency


Pure (unslotted) ALOHA

sect unslotted Aloha simpler no synchronizationsect when frame first arrives

bull transmit immediately sect collision probability increases

bull frame sent at t0 collides with other frames sent in [t0-1t0+1]


Pure ALOHA efficiencyP(success by given node) = P(node transmits)

P(no other node transmits in [t0-1t0] P(no other node transmits in [t0t0+1]

= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)

hellip choosing optimum p and then letting n

= 1(2e) = 18

even worse than slotted Aloha


CSMA (carrier sense multiple access)

CSMA listen before transmitsect if channel sensed idle transmit entire

frame sect if channel sensed busy defer

transmission

sect human analogy donrsquot interrupt others


CSMA collisions

sect collisions can still occur propagation delay means two nodes may not hear each otherrsquos transmission

sect collision entire packet transmission time wastedbull distance amp

propagation delay play role in determining collision probability

spatial layout of nodes


CSMACD (collision detection)

CSMACD carrier sensing deferral as in CSMAbull collisions detected within short timebull colliding transmissions aborted reducing channel wastage

sect collision detectionbull easy in wired LANs measure signal strengths compare

transmitted received signalsbull difficult in wireless LANs received signal strength

overwhelmed by local transmission strength sect human analogy the polite conversationalist





Ethernet CSMACD algorithm

1 NIC receives datagram from network layer creates frame

2 If NIC senses channel idle starts frame transmission If NIC senses channel busy waits until channel idle then transmits

3 If NIC transmits entire frame without detecting another transmission NIC is done with frame

4 If NIC detects another transmission while transmitting aborts and sends jam signal

5 After aborting NIC enters binary (exponential) backoff bull after mth collision NIC

chooses K at random from 012 hellip 2m-1 NIC waits K512 bit times returns to Step 2

bull longer backoff interval with more collisions


CSMACD efficiency

sect tprop = max prop delay between 2 nodes in LANsect ttrans = time to transmit max-size frame

sect efficiency goes to 1 bull as tprop goes to 0bull as ttrans goes to infinity

sect better performance than ALOHA and simple cheap decentralized

transprop ttefficiency

511

+=


ldquoTaking turnsrdquo MAC protocols

channel partitioning MAC protocolssect share channel efficiently and fairly at high loadsect inefficient at low load delay in channel access 1N

bandwidth allocated even if only 1 active node random access MAC protocols

sect efficient at low load single node can fully utilize channel

sect high load collision overheadldquotaking turnsrdquo protocols

look for best of both worlds


pollingsect master node ldquoinvitesrdquo

slave nodes to transmit in turn

sect typically used with ldquodumbrdquo slave devices

sect concernsbull polling overhead bull latencybull single point of

failure (master)

master

slaves

poll

data

data



token passingsect control token passed from

one node to next sequentially

sect token messagesect concerns

sect token overhead sect latencysect single point of failure

(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP

cable modemtermination system

sect multiple 40Mbps downstream (broadcast) channelssect single CMTS transmits into channels

sect multiple 30 Mbps upstream channelssect multiple access all users contend for certain upstream

channel time slots (others assigned)

Cable access network

cablemodemsplitter

hellip

hellip

Internet frames TV channels control transmitted downstream at different frequencies

upstream Internet frames TV control transmitted upstream at different frequencies in time slots


DOCSIS data over cable service interface spec sect FDM over upstream downstream frequency channelssect TDM upstream some slots assigned some have contention

bull downstream MAP frame assigns upstream slotsbull request for upstream slots (and data) transmitted

random access (binary backoff) in selected slots

MAP frame forInterval [t1 t2]

Residences with cable modems

Downstream channel i

Upstream channel j

t1 t2

Assigned minislots containing cable modemupstream data frames

Minislots containing minislots request frames

cable headend

CMTS



Summary of MAC protocols

sect channel partitioning by time frequency or codebull Time Division Frequency Division

sect random access (dynamic) bull ALOHA S-ALOHA CSMA CSMACDbull carrier sensing easy in some technologies (wire) hard

in others (wireless)bull CSMACD used in Ethernetbull CSMACA used in 80211

sect taking turnsbull polling from central site token passingbull Bluetooth FDDI token ring


Quiz Time

5 DataLink Layer 5-43




protocols64 LANs






MAC addresses and ARP

sect 32-bit IP address bull network-layer address for interfacebull used for layer 3 (network layer) forwarding

sect MAC (or LAN or physical or Ethernet) addressbull function used lsquolocallyrdquo to get frame from one interface to

another physically-connected interface (same network in IP-addressing sense)

bull 48 bit MAC address (for most LANs) burned in NIC ROM also sometimes software settable

bull eg 1A-2F-BB-76-09-AD

hexadecimal (base 16) notation(each ldquonumeralrdquo represents 4 bits)


LAN addresses and ARPeach adapter on LAN has unique LAN address

adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN(wired orwireless)


LAN addresses (more)

sect MAC address allocation administered by IEEEsect manufacturer buys portion of MAC address space

(to assure uniqueness)sect analogy

bull MAC address like Social Security Numberbull IP address like postal address

sect MAC flat address portability bull can move LAN card from one LAN to another

sect IP hierarchical address not portablebull address depends on IP subnet to which node is

attached


ARP address resolution protocol

ARP table each IP node (host router) on LAN has table

bull IPMAC address mappings for some LAN nodes

lt IP address MAC address TTLgt

bull TTL (Time To Live) time after which address mapping will be forgotten (typically 20 min)

Question how to determineinterfacersquos MAC address knowing its IP address

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788


ARP protocol same LANsect A wants to send datagram

to Bbull Brsquos MAC address not in

Arsquos ARP tablesect A broadcasts ARP query

packet containing Bs IP address

bull destination MAC address = FF-FF-FF-FF-FF-FF

bull all nodes on LAN receive ARP query

sect B receives ARP packet replies to A with its (Bs) MAC address

bull frame sent to Arsquos MAC address (unicast)

sect A caches (saves) IP-to-MAC address pair in its ARP table until information becomes old (times out)

bull soft state information that times out (goes away) unless refreshed

sect ARP is ldquoplug-and-playrdquobull nodes create their ARP

tables without intervention from net administrator


walkthrough send datagram from A to B via Rsect focus on addressing ndash at IP (datagram) and MAC layer (frame)sect assume A knows Brsquos IP addresssect assume A knows IP address of first hop router R (how)sect assume A knows Rrsquos MAC address (how)

Addressing routing to another LAN

R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222

sect A creates IP datagram with IP source A destination B sect A creates link-layer frame with Rs MAC address as destination address

frame contains A-to-B IP datagram

MAC src 74-29-9C-E8-FF-55MAC dest E6-E9-00-17-BB-4B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

sect frame sent from A to R

IPEthPhy

sect frame received at R datagram removed passed up to IP


IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222

sect R forwards datagram with IP source A destination B sect R creates link-layer frame with Bs MAC address as destination address


MAC src 1A-23-F9-CD-06-9BMAC dest 49-BD-D2-C7-56-2A

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B

Addressing routing to another LANsect R forwards datagram with IP source A destination B sect R creates link-layer frame with Bs MAC address as destination address


IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B

Addressing routing to another LANsect R forwards datagram with IP source A destination B sect R creates link-layer frame with Bs MAC address as dest frame contains

A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy

6-55Link Layer and LANs Check out the online interactive exercises for more examples httpgaiacsumassedukurose_rossinteractive




protocols64 LANs






Ethernetldquodominantrdquo wired LAN technology sect single chip multiple speeds (eg Broadcom BCM5761)sect first widely used LAN technologysect simpler cheapsect kept up with speed race 10 Mbps ndash 10 Gbps

Metcalfersquos Ethernet sketch6-57Link Layer and LANs

Ethernet physical topologysect bus popular through mid 90s

bull all nodes in same collision domain (can collide with each other)

sect star prevails todaybull active switch in centerbull each ldquospokerdquo runs a (separate) Ethernet protocol (nodes

do not collide with each other)

switch

bus coaxial cablestar


Ethernet frame structure

sending adapter encapsulates IP datagram (or other network layer protocol packet) in Ethernet frame

preamble sect 7 bytes with pattern 10101010 followed by one

byte with pattern 10101011sect used to synchronize receiver sender clock rates

destaddress

sourceaddress

data (payload) CRCpreamble

type


Ethernet frame structure (more)sect addresses 6 byte source destination MAC addresses

bull if adapter receives frame with matching destination address or with broadcast address (eg ARP packet) it passes data in frame to network layer protocol

bull otherwise adapter discards framesect type indicates higher layer protocol (mostly IP but

others possible eg Novell IPX AppleTalk)sect CRC cyclic redundancy check at receiver

bull error detected frame is dropped

destaddress

sourceaddress


type


Ethernet unreliable connectionless

sect connectionless no handshaking between sending and receiving NICs

sect unreliable receiving NIC doesnt send acks or nacks to sending NICbull data in dropped frames recovered only if initial

sender uses higher layer rdt (eg TCP) otherwise dropped data lost

sect Ethernetrsquos MAC protocol unslotted CSMACD with binary backoff


8023 Ethernet standards link amp physical layers

sect many different Ethernet standardsbull common MAC protocol and frame formatbull different speeds 2 Mbps 10 Mbps 100 Mbps 1Gbps

10 Gbps 40 Gbpsbull different physical layer media fiber cable


linkphysical

MAC protocoland frame format

100BASE-TX

100BASE-T4

100BASE-FX100BASE-T2

100BASE-SX 100BASE-BX

fiber physical layercopper (twisterpair) physical layer





protocols64 LANs






Ethernet switchsect link-layer device takes an active role

bull store forward Ethernet framesbull examine incoming framersquos MAC address

selectively forward frame to one-or-more outgoing links when frame is to be forwarded on segment uses CSMACD to access segment

sect transparentbull hosts are unaware of presence of switches

sect plug-and-play self-learningbull switches do not need to be configured


Switch multiple simultaneous transmissions

sect hosts have dedicated direct connection to switch

sect switches buffer packetssect Ethernet protocol used on each

incoming link but no collisions full duplexbull each link is its own collision

domainsect switching A-to-Arsquo and B-to-Brsquo

can transmit simultaneously without collisions switch with six interfaces

(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Switch forwarding table

Q how does switch know Arsquoreachable via interface 4 Brsquoreachable via interface 5

switch with six interfaces(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6sect A each switch has a switch table each entrysect (MAC address of host interface

to reach host time stamp)sect looks like a routing table

Q how are entries created maintained in switch table

sect something like a routing protocol


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6

Switch self-learningsect switch learns which hosts

can be reached through which interfaces

bull when frame received switch ldquolearnsrdquo location of sender incoming LAN segment

bull records senderlocation pair in switch table

A Arsquo

Source ADest Arsquo

MAC addr interface TTLSwitch table

(initially empty)A 1 60


Switch frame filteringforwarding

when frame received at switch

1 record incoming link MAC address of sending host2 look up switch table using MAC destination address3 if entry found for destination

then if destination on segment from which frame arrived

then drop frameelse forward frame on interface indicated by entry

else flood forward on all interfaces except arriving

interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6

Self-learning forwarding exampleA Arsquo

Source ADest Arsquo

MAC addr interface TTLswitch table


A ArsquoA ArsquoA ArsquoA ArsquoA Arsquo

sect frame destination Arsquo location unknown flood

Arsquo A

sect destination A location known

Arsquo 4 60

selectively send on just one link


Interconnecting switches

self-learning switches can be connected together

Q sending from A to G - how does S1 know to forward frame destined to G via S4 and S3sect A self learning (works exactly the same as in

single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G


Self-learning multi-switch exampleSuppose C sends frame to I I responds to C

sect Q show switch tables and packet forwarding in S1 S2 S3 S4

A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4

Institutional network

to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers

both are store-and-forward sect routers network-layer

devices (examine network-layer headers)

sect switches link-layer devices (examine link-layer headers)

both have forwarding tablessect routers compute tables using

routing algorithms IP addresses

sect switches learn forwarding table using flooding learning MAC addresses


linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs






Data center networks

sect 10rsquos to 100rsquos of thousands of hosts often closely coupled in close proximitybull e-business (eg Amazon)bull content-servers (eg YouTube Akamai Apple Microsoft)bull search engines data mining (eg Google)

sect challengessect multiple applications each

serving massive numbers of clients

sect managingbalancing load avoiding processing networking data bottlenecks

Inside a 40-ft Microsoft container Chicago data center


Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router

Data center networks load balancer application-layer routingsect receives external client requestssect directs workload within data centersect returns results to external client (hiding data

center internals from client)


Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8

Data center networks sect rich interconnection among switches racks

bull increased throughput between racks (multiple routing paths possible)

bull increased reliability via redundancy





protocols64 LANs






Synthesis a day in the life of a web request

sect journey down protocol stack completebull application transport network link

sect putting-it-all-together synthesisbull goal identify review understand protocols (at all

layers) involved in seemingly simple scenario requesting www page

bull scenario student attaches laptop to campus network requestsreceives wwwgooglecom


A day in the life scenario

Comcast network 68800013

Googlersquos network 64233160019 64233169105

web server

DNS server

school network 68802024

web page

browser


Network Layer 4-93

DHCP client-server scenarioDHCP server 223125 arriving

client

time

DHCP discover

src 0000 68 dest 25525525525567yiaddr 0000transaction ID 654

DHCP offersrc 223125 67 dest 255255255255 68yiaddrr 223124transaction ID 654Lifetime 3600 secs

DHCP requestsrc 0000 68 dest 255255255255 67yiaddrr 223124transaction ID 655Lifetime 3600 secs

DHCP ACKsrc 223125 67 dest 255255255255 68yiaddrr 223124transaction ID 655Lifetime 3600 secs

router(runs DHCP)

A day in the lifehellip connecting to the Internet

sect connecting laptop needs to get its own IP address addr of first-hop router addr of DNS server use DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP

sect DHCP request encapsulatedin UDP encapsulated in IP encapsulated in 8023Ethernet

sect Ethernet frame broadcast(dest FFFFFFFFFFFF) on LAN received at router running DHCP server

sect Ethernet demuxed to IP demuxed UDP demuxed to DHCP


router(runs DHCP)

sect DHCP server formulates DHCP ACK containing clientrsquos IP address IP address of first-hop router for client name amp IP address of DNS server

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

sect encapsulation at DHCP server frame broadcast (dest FFFFFFFFFFFF) on LAN demultiplexing at client

Client now has IP address knows name amp addr of DNS server IP address of its first-hop router

sect DHCP client receives DHCP ACK reply



router(runs DHCP)

A day in the lifehellip ARP (before DNS before HTTP)

sect before sending HTTP request need IP address of wwwgooglecom DNS

DNSUDP

IPEthPhy

DNSDNS

DNS

sect DNS query created encapsulated in UDP encapsulated in IP encapsulated in Eth To send frame to router need MAC address of router interface ARP

sect ARP query broadcast received by router which replies with ARP reply (via self learning at the Eth switch) giving MAC address of router interface

sect client now knows MAC address of first hop router so can now send frame containing DNS query

ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS

sect IP datagram containing DNS query forwarded via LAN switch from client to 1st hop router

sect IP datagram forwarded from campus network into Comcast network routed (tables created by RIP OSPF IS-IS andor BGProuting protocols) to DNS server

sect demuxed to DNS serversect DNS server replies to client

with IP address of wwwgooglecom


DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS

A day in the lifehellip using DNS


router(runs DHCP)

A day in the lifehellipTCP connection carrying HTTP

HTTPTCPIPEthPhy

HTTP

sect to send HTTP request client first opens TCP socket to web server

sect TCP SYN segment (step 1 in 3-way handshake) inter-domain routed to web server

sect TCP connection established64233169105web server

SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

sect web server responds with TCP SYNACK (step 2 in 3-way handshake)hellip


router(runs DHCP)

A day in the lifehellip HTTP requestreply HTTPTCPIPEthPhy

HTTP

sect HTTP request sent into TCP socket

sect IP datagram containing HTTP request routed to wwwgooglecom

sect IP datagram containing HTTP reply routed back to client

64233169105web server

HTTPTCPIPEthPhy

sect web server responds with HTTP reply (containing web page)

HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

sect web page finally () displayed


Chapter 6 Summarysect principles behind data link layer services

bull error detection correctionbull sharing a broadcast channel multiple accessbull link layer addressing

sect instantiation and implementation of various link layer technologiesbull Ethernetbull switched LANS VLANsbull virtualized networks as a link layer MPLS

sect synthesis a day in the life of a web request

6-100

Link Layer and LANs

Chapter 6 letrsquos take a breathsect journey down protocol stack complete (except

PHY)sect solid understanding of networking principles

practicesect hellip could stop here hellip but lots of interesting

topicsbull wirelessbull multimediabull security

6-101

Link Layer and LANs

Chapter 6 Link layer and LANsour goalssect understand principles behind link layer

servicesbull error detection correctionbull sharing a broadcast channel multiple accessbull link layer addressingbull local area networks Ethernet VLANs

sect instantiation implementation of various link layer technologies





protocols64 LANs











Link layer context










algorithm













retransmission


at same time







software firmware

controller


cpu memory

host bus (eg PCI)

network adaptercard


link

linkphysical











datagram datagram

datagram

frame





protocols64 LANs








otherwise


Parity checking


errors


0 0



















CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G



Quiz Time




protocols64 LANs

















time










4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable



Quiz Time








Slotted ALOHA














sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

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S1

C D

E

FS2

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HI

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A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs




protocols64 LANs











Link layer context










algorithm













retransmission


at same time







software firmware

controller


cpu memory

host bus (eg PCI)

network adaptercard


link

linkphysical











datagram datagram

datagram

frame





protocols64 LANs








otherwise


Parity checking


errors


0 0



















CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G



Quiz Time




protocols64 LANs

















time










4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable



Quiz Time








Slotted ALOHA














sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

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Source ADest Arsquo





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single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs






Link layer context










algorithm













retransmission


at same time







software firmware

controller


cpu memory

host bus (eg PCI)

network adaptercard


link

linkphysical











datagram datagram

datagram

frame





protocols64 LANs








otherwise


Parity checking


errors


0 0



















CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G



Quiz Time




protocols64 LANs

















time










4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable



Quiz Time








Slotted ALOHA














sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

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1 2

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6





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Arsquo

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A Arsquo

Source ADest Arsquo










interface


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Arsquo

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1 2

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6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs












retransmission


at same time







software firmware

controller


cpu memory

host bus (eg PCI)

network adaptercard


link

linkphysical











datagram datagram

datagram

frame





protocols64 LANs








otherwise


Parity checking


errors


0 0



















CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G



Quiz Time




protocols64 LANs

















time










4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable



Quiz Time








Slotted ALOHA














sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

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Source ADest Arsquo





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single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs





software firmware

controller


cpu memory

host bus (eg PCI)

network adaptercard


link

linkphysical











datagram datagram

datagram

frame





protocols64 LANs








otherwise


Parity checking


errors


0 0



















CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G



Quiz Time




protocols64 LANs

















time










4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable



Quiz Time








Slotted ALOHA














sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

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6





A

Arsquo

B

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Crsquo

1 2

345






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Arsquo

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A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs










datagram datagram

datagram

frame





protocols64 LANs








otherwise


Parity checking


errors


0 0



















CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G



Quiz Time




protocols64 LANs

















time










4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable



Quiz Time








Slotted ALOHA














sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs




protocols64 LANs








otherwise


Parity checking


errors


0 0



















CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G



Quiz Time




protocols64 LANs

















time










4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable



Quiz Time








Slotted ALOHA














sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

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Brsquo C

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Arsquo

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A Arsquo

Source ADest Arsquo










interface


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Source ADest Arsquo





Arsquo A


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single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs



otherwise


Parity checking


errors


0 0



















CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G



Quiz Time




protocols64 LANs

















time










4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable



Quiz Time








Slotted ALOHA














sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

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1 2

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Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

Parity checking


errors


0 0



















CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G



Quiz Time




protocols64 LANs

















time










4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable



Quiz Time








Slotted ALOHA














sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

















CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G



Quiz Time




protocols64 LANs

















time










4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable



Quiz Time








Slotted ALOHA














sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

Quiz Time




protocols64 LANs

















time










4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable



Quiz Time








Slotted ALOHA














sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

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6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs




protocols64 LANs

















time










4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable



Quiz Time








Slotted ALOHA














sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs












time










4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable



Quiz Time








Slotted ALOHA














sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs






4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable



Quiz Time








Slotted ALOHA














sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

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Brsquo C

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Source ADest Arsquo





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single-switch case)

A

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S1

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A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs






turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable



Quiz Time








Slotted ALOHA














sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

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Crsquo

1 2

345






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1 2

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6





A Arsquo

Source ADest Arsquo










interface


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Arsquo

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1 2

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Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs




send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable



Quiz Time








Slotted ALOHA














sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs


bands 256 idle

frequ

ency

ban

ds

time

FDM cable



Quiz Time








Slotted ALOHA














sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

Quiz Time








Slotted ALOHA














sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs








Slotted ALOHA














sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs




sect simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

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6





A

Arsquo

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A

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A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

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6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs




transmission



CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

CSMA collisions
























CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs



















CSMACD efficiency





511

+=













failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs





(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs







Upstream channel j

t1 t2



cable headend

CMTS









Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs







Quiz Time





protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

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1 2

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6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

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1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs




protocols64 LANs















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs










adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53









attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs







attached








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs







1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788

















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

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Arsquo

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Arsquo

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Source ADest Arsquo





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single-switch case)

A

B

S1

C D

E

FS2

S4

S3

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G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs
















R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

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1 2

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6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

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6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

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6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4








protocols64 LANs


















(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo










interface


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy





protocols64 LANs












switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


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Server racks

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DNS server


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Network Layer 4-93


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IPEthPhy

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DHCP

DHCP

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SYN

SYN

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SYN

SYN

SYN

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SYNACK

SYNACK

SYNACK

SYNACK

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SYNACK



router(runs DHCP)


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6-100

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6-101

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1A-23-F9-CD-06-9B222222222220

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Switches vs routers








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protocols64 LANs













Server racks

TOR switches

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Server racks

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Tier-1 switches

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web server

DNS server


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Network Layer 4-93


client

time

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router(runs DHCP)



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IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

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DHCP

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router(runs DHCP)


DHCPUDP

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router(runs DHCP)



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DNS serverDNSUDP

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HTTPTCPIPEthPhy

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SYN

SYN

SYN

SYN

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6-100

Link Layer and LANs





6-101

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Switches vs routers








linkphysical

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linkphysical

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Server racks

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ARP query

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ARP

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DNSDNS

DNS

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DNS serverDNSUDP

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HTTPTCPIPEthPhy

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SYN

SYN

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Switches vs routers








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frame

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protocols64 LANs













Server racks

TOR switches

Tier-1 switches

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HTTPTCPIPEthPhy

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6-100

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protocols64 LANs













Server racks

TOR switches

Tier-1 switches

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Tier-1 switches

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DNS serverDNSUDP

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HTTPTCPIPEthPhy

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SYN

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6-100

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protocols64 LANs













Server racks

TOR switches

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Server racks

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Tier-1 switches

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protocols64 LANs















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DNS server


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Network Layer 4-93


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time

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router(runs DHCP)



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IPEthPhy

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DHCP

DHCP

DHCP

DHCP

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DHCP

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router(runs DHCP)


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protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

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protocols64 LANs















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Network Layer 4-93


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time

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router(runs DHCP)



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IPEthPhy

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SYN

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linkphysical

networklink

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linkphysical

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datagram


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frame

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Server racks

TOR switches

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TOR switches

Tier-1 switches

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DNS server


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Network Layer 4-93


client

time

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router(runs DHCP)



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Switches vs routers








linkphysical

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linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs




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G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

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12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs







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B

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G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

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single-switch case)

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B

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12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs




single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs



A

B

S1

C D

E

FS2

S4

S3

HI

G


12

4

3

12

3

1 23

41

23

4


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs


to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frame

frame

framedatagram





protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs




protocols64 LANs













Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs








Server racks

TOR switches

Tier-1 switches

Tier-2 switches

Load balancer

Load balancer

B

1 2 3 4 5 6 7 8

A C

Border router

Access router




Internet

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

Server racks

TOR switches

Tier-1 switches

Tier-2 switches

1 2 3 4 5 6 7 8








protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs




protocols64 LANs















web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs










web server

DNS server


web page

browser


Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

Network Layer 4-93


client

time

DHCP discover





router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

router(runs DHCP)



DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCPDHCP





router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

router(runs DHCP)


DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCPUDP

IPEthPhy

DHCP

DHCP

DHCP

DHCP

DHCP






router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

router(runs DHCP)



DNSUDP

IPEthPhy

DNSDNS

DNS




ARP query

EthPhy

ARP

ARP

ARP reply


router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

router(runs DHCP)

DNSUDP

IPEthPhy

DNSDNS

DNS

DNS

DNS






DNS serverDNSUDP

IPEthPhy

DNS

DNS

DNS

DNS



router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

router(runs DHCP)


HTTPTCPIPEthPhy

HTTP




SYN

SYN

SYN

SYN

TCPIPEthPhy

SYN

SYN

SYN

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK

SYNACK



router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs

router(runs DHCP)


HTTP





HTTPTCPIPEthPhy


HTTP

HTTP

HTTPHTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP

HTTP







6-100

Link Layer and LANs





6-101

Link Layer and LANs





6-100

Link Layer and LANs





6-101

Link Layer and LANs





6-101

Link Layer and LANs

Chapter 6 The Link Layer and LANshomepage.ntu.edu.tw/~pollyhuang/teach/intro-cn... · §each...

Documents

Transcript of Chapter 6 The Link Layer and LANshomepage.ntu.edu.tw/~pollyhuang/teach/intro-cn... · §each...