N Read: 4.4 n Problems: 4.1, Web 6.1 n Design #1 due 1 February (Live) u 8 February (Async DL) u...

Read: 4.4Read: 4.4 Problems: 4.1, Web 6.1Problems: 4.1, Web 6.1 Design #1 due 1 February (Live)Design #1 due 1 February (Live)

8 February (Async DL)8 February (Async DL) Late = -1 per working dayLate = -1 per working day

Quiz #1Quiz #1 Lecture 12, 4 February (Live)Lecture 12, 4 February (Live) << 11 February (Async Distance Learning) 11 February (Async Distance Learning)

ECEN4533 Data CommunicationsECEN4533 Data CommunicationsLecture #9 28 January 2013Lecture #9 28 January 2013Dr. George ScheetsDr. George Scheets


Read: 5.1 - 5.4Read: 5.1 - 5.4 Problems: 5.1 - 5.3Problems: 5.1 - 5.3 Design #1 due 1 February (Live)Design #1 due 1 February (Live)


Quiz #1Quiz #1 Lecture 12, 4 February (Live)Lecture 12, 4 February (Live) << 11 February (Async Distance Learning) 11 February (Async Distance Learning)



Read: 5.7 - 5.8 Read: 5.7 - 5.8 Problems: NoneProblems: None Design #1 due Design #1 due 1 February (Live)1 February (Live)


Quiz #1 (open book & notes)Quiz #1 (open book & notes) Lecture 12, 4 February (Live)Lecture 12, 4 February (Live) << 11 February (Async Distance Learning) 11 February (Async Distance Learning)

ECEN4533 Data CommunicationsECEN4533 Data CommunicationsLecture #11 1 February 2013Lecture #11 1 February 2013Dr. George ScheetsDr. George Scheets

ECEN4533 Data CommunicationsECEN4533 Data CommunicationsLecture #11 1 February 2013Lecture #11 1 February 2013Dr. George ScheetsDr. George Scheets

POTS at the CO SwitchPOTS at the CO Switch Band Pass Filter suppresses energy Band Pass Filter suppresses energy

outside voice bandwidth (300 - 3,400 Hz)outside voice bandwidth (300 - 3,400 Hz)

Band Pass Filter

(.3 - 3.4KHz)

SamplerFs = 8 KHz

TwistedPair Cable

Quantize256 levels

Code8 bits/sample

64 Kbps

A/D Converter

Nyquist's Sampling TheoremNyquist's Sampling Theorem

Want to have a shot at perfectly Want to have a shot at perfectly reconstructing a sampled signal?reconstructing a sampled signal? Sample at a rate > twice the maximum frequency.Sample at a rate > twice the maximum frequency.

Example: Phone system Example: Phone system Maximum frequency around 3.5 KHz, fs = 8 KspsMaximum frequency around 3.5 KHz, fs = 8 Ksps

Example: Compact DiskExample: Compact Disk Maximum frequency around 20 KHz, fs = 44.1 KspsMaximum frequency around 20 KHz, fs = 44.1 Ksps

Video undersamplingVideo undersampling

time t=0

time = 2/30

time = 1/30

30 video stills/second27 wheel revs/second0.9 wheel revs/still

Spoke would appearto be moving backwards.

A/D Converter

PC Dial-Up Modems & POTSPC Dial-Up Modems & POTS PC Bit Stream has a significant amount of energy below 0.5 PC Bit Stream has a significant amount of energy below 0.5

KHzKHz Modems shift the energy into the pass band of the filter Modems shift the energy into the pass band of the filter

PC

Quantize256 levels

Code8 bits/sample

64 Kbps

Band Pass Filter

(.3 - 3.4 KHz)

SamplerFs = 8 KHz

TwistedPair Cable

Sources of POTS delaySources of POTS delay

Local Loop

PCMCoder TDM Trunk

POTSTSI

POTSTSI

IntermediateDigitalVoice

Switches

...

TDM TrunkLocal Loop

PCMCoder

Trunk resources are dedicatedto each voice call via TDM.

Source CO

Destination CO

Example) Coding aMicrophone Output

Example) Coding aMicrophone Output

time (sec)

m(t) volts (air pressure)

Energy from about 300 - 3,400 Hz.

A/D ConvertorA/D Convertor

time (sec)

m(t) volts (air pressure)

Step #1)Sample the waveform at rate > 2*Max Frequency.Telephone voice is sampled at 8,000 samples/second.

1/8000 second

A/D Convertor. 1 bit/sample.A/D Convertor. 1 bit/sample.

time (sec)

Example) N = 2. Assign 0 or 1 to voltage.

0 < Voltage < +5v, Assign Logic 1-5v < Voltage < 0, Assign Logic 0

3.62 v, output a 1

t1

Bit Stream Out = 1111110000111...

A/D Convertor. 1 bit/sample.A/D Convertor. 1 bit/sample.Example) N = 2. Assign 0 or 1 to voltage.

Far side gets... 1111110000111 (13 samples)Need to output 13 voltages.What does a 1 represent? A 0?

Receive a 1? Output +2.5 v (mid-range)Receive a 0? Output -2.5 v (mid-range)

Hold the voltage until next sample

0 < Voltage < +5v, Assign Logic 1-5v < Voltage < 0, Assign Logic 0

A/D Convertor. 1 bit/sample.A/D Convertor. 1 bit/sample.

Input to the transmitter.Output at the receiver.

Considerable Round-Off error exists.

+2.5 v

-2.5 v

time (sec)

Example) N = 4. Assign 00, 01, 10 or 11.

2.5 < Voltage < 5 , Assign 110 < Voltage < 2.5, Assign 10-2.5 < Voltage < 0, Assign 00-5 < Voltage < -2.5, Assign 01

3.62 v, Assign 11

t1

Bit Stream Out =11111011111100 000000101011...

+2.5 v

-2.5 v

A/D Convertor. 2 bits/sampleA/D Convertor. 2 bits/sample

A/D Convertor. 2 bits/sample.A/D Convertor. 2 bits/sample.

Input to the transmitter.Output at the receiver.

Receive 11? Output 3.75vReceive 10? Output 1.25vReceive 00? Output -1.25vReceive 01? Output -3.75vReduced Round-Off error exists.

+3.75 v

+1.25 v

-1.25 v

-3.75 v

Circuit Switched Voice (POTS)Circuit Switched Voice (POTS) Telephone System uses Pulse Code ModulationTelephone System uses Pulse Code Modulation

Equal length code word assigned to all voltagesEqual length code word assigned to all voltages N = 256 voltage levelsN = 256 voltage levels LogLog22256 = 8 bits per code word256 = 8 bits per code word

A/D ConverterA/D Converter samples voice 8,000 times/secondsamples voice 8,000 times/second rounds off voice to one of 256 voltage levelsrounds off voice to one of 256 voltage levels transmits 8 bits to far sidetransmits 8 bits to far side

D/A ConverterD/A Converter receives 8 bit code wordreceives 8 bit code word outputs one of 256 voltage levels for 1/8000th sec.outputs one of 256 voltage levels for 1/8000th sec.

1/8th Second of Voice1/8th Second of Voice

Sampling & Quantizing ExamplesSampling & Quantizing Examples fs = 16 KHzfs = 16 KHz

4096 quantiles 4096 quantiles 256 quantiles (approximate phone quality)256 quantiles (approximate phone quality) 32 quantiles 32 quantiles 4 quantiles (generally 2 levels used!)4 quantiles (generally 2 levels used!)

4096 quantiles4096 quantiles fs = 16 KHzfs = 16 KHz fs = 8 KHz (some interference)fs = 8 KHz (some interference) fs = 2 KHzfs = 2 KHz fs = 1 KHzfs = 1 KHz

SONET HierarchySONET Hierarchy Basic Building Block:

51.84 Mbps STS-1 Frame 8,000 frames/second 810 bytes/frame, 36 bytes for OA&M

Optical Carrier-N? N byte interleaved STS-1 signals (TDM)

OC-1OC-1 51.84 Mbps51.84 MbpsOC-3OC-3 155.52 Mbps155.52 MbpsOC-12OC-12 622.08 Mbps622.08 MbpsOC-48OC-48 2.48832 Gbps2.48832 GbpsOC-192OC-192 9.95328 Gbps9.95328 GbpsOC-768OC-768 39.81312 Gbps 39.81312 Gbps

T Carrier & SONETT Carrier & SONET Technology used in Leased LinesTechnology used in Leased Lines Mid-1960’s (T Carrier) & Mid-1960’s (T Carrier) &

Late-1980’s (SONET) technologyLate-1980’s (SONET) technology Covers OSI Layers 1 & 2 (Covers OSI Layers 1 & 2 (notnot packet-aware!) packet-aware!) Guaranteed Bandwidth usingGuaranteed Bandwidth using

Circuit Switching & TDMCircuit Switching & TDM End-to-End path mapped in advanceEnd-to-End path mapped in advance Provides fixed number of bytes, 8000 times second, for customer useProvides fixed number of bytes, 8000 times second, for customer use As they arrive, switches repetitively move input bytes to appropriate output & TDM slot As they arrive, switches repetitively move input bytes to appropriate output & TDM slot

Leased Line NetworksLeased Line Networks Last Mile ConnectivityLast Mile Connectivity

Fractional T-1 (4 Wire Twisted Pair)Fractional T-1 (4 Wire Twisted Pair)N*64 Kbps, N = 1 - 23N*64 Kbps, N = 1 - 23

T-1 (4 Wire Twisted Pair) T-1 (4 Wire Twisted Pair) 1.536 Mbps (24*64 Kbps)1.536 Mbps (24*64 Kbps)

Fractional T-3 (Coax)Fractional T-3 (Coax)N T-1's, N = 1 - 27N T-1's, N = 1 - 27

T-3 (Coax) T-3 (Coax) 28 T-1's + Overhead (45 Mbps)28 T-1's + Overhead (45 Mbps)

Last Mile or Long Haul ConnectivityLast Mile or Long Haul Connectivity OC- N, N = 1, 3, 12, 48, & 192 (SONET)OC- N, N = 1, 3, 12, 48, & 192 (SONET)

N*51.84 Mbps (Fiber)N*51.84 Mbps (Fiber)

ISO OSI Seven Layer ModelLeased Line (Circuit Switched, TDM) Organized around Frames:1/8000th second entity

ISO OSI Seven Layer ModelLeased Line (Circuit Switched, TDM) Organized around Frames:1/8000th second entity

Layer 7 ApplicationLayer 7 Application Layer 6 Presentation Layer 6 Presentation Layer 5 SessionLayer 5 Session Layer 4 TransportLayer 4 Transport Layer 3 Network Layer 3 Network Layer 2 Data Link Layer 2 Data Link SONET, T-Carrier (PPP)SONET, T-Carrier (PPP) Layer 1 Physical Layer 1 Physical SONET, T-CarrierSONET, T-Carrier

Carrier Switches are byte-aware, NOT packet-aware.Carrier Switches are byte-aware, NOT packet-aware.

Leased Line Packet FormatLeased Line Packet Format

Data + Padding

7 20 20 6-1460

IP TCPPoint-to-PointProtocol

Leased Line BackboneLeased Line Backbone

TrunksLeased Line

Leased Line ‘Cloud’Trunk capacity shared via TDM & Circuit Switching

Cross-ConnectCross-Connect

LAN

LAN

Carrier Leased Line NetworkCarrier Leased Line Network

Nailed up end-to-end connectivity (a Circuit).Bit pipe. No packet processing between Routers.


OC-48TrunksLeased Line

T1

T1

Circuit Switched connections waste bandwidth for bursty traffic.Circuit Switched connections waste bandwidth for bursty traffic.

time

traffic 1.536 Mbps Line Speed

146 Kbps Average

Idle Time >> Active TimeLoad = 9.456%

Carrier Leased Line NetworkCarrier Leased Line Network

Route once (circuit setup).Path through Network nailed down.Switches forward based on Time Slots per 1/8000th sec.

TDM SwitchTDM Switch

TrunksAccess Line

ATMFrame RelayRouter

Long Haul U.S. TrafficLong Haul U.S. Traffic Primarily carried on fiberPrimarily carried on fiber Running SONET or OTNRunning SONET or OTN Generally OC-48, 192, & 768; some 100 GbpsGenerally OC-48, 192, & 768; some 100 Gbps Wavelength Division Multiplexing common Wavelength Division Multiplexing common

Each OC-N drives a laserEach OC-N drives a laser lasers tuned to different frequencieslasers tuned to different frequencies injected onto same fiber strandinjected onto same fiber strand

SONET BW parceled out to usersSONET BW parceled out to users Circuit SwitchingCircuit Switching TDMTDM

WDM: 32 OC-768’s (1.274 Tbps)WDM: 32 OC-768’s (1.274 Tbps)

#1 STS-768 Laser @ f1

Laser @ f2

Laser @ f32

#2 STS-768

#32 STS-768

Detector #1

Detector#2

Detector#32

#1 STS-768

#2 STS-768

#32 STS-768

OpticalCombiner

OpticalSplitter

Fiber in theground

Systems are also available that can map an arbitrary input(doesn’t have to be SONET or OTN based) onto an optical wave.

Leased LinesLeased Lines Covers OSI Layers 1 & 2Covers OSI Layers 1 & 2 64 Kbps - 10 Gbps Line Speed64 Kbps - 10 Gbps Line Speed TDM, Circuit SwitchedTDM, Circuit Switched Based on 1960 & 1990 technologyBased on 1960 & 1990 technology

Switches are byte awareSwitches are byte aware Common: Corporate ConnectivityCommon: Corporate Connectivity Very Common: ISP ConnectivityVery Common: ISP Connectivity

Page InfoNov 2007

IEEE 802.3 Ethernet IEEE 802.3 Ethernet Covers OSI Layers 1 & 2Covers OSI Layers 1 & 2 10 Mbps Line Speed10 Mbps Line Speed Packet Switch, StatMuxPacket Switch, StatMux Based on late 1970’s technologyBased on late 1970’s technology

Computing Power & Memory was ExpensiveComputing Power & Memory was Expensive Initially Shared SystemInitially Shared System

Polite Conversation (CSMA/CD)Polite Conversation (CSMA/CD) One Node talks at a timeOne Node talks at a time Need to talk? Wait til line quietNeed to talk? Wait til line quiet Nobody deliberately butts inNobody deliberately butts in

Switched Ethernet now more commonSwitched Ethernet now more common

ISO OSI Seven Layer ModelEthernet (Packet Switched, StatMux)ISO OSI Seven Layer ModelEthernet (Packet Switched, StatMux)

Layer 7 ApplicationLayer 7 Application Layer 6 Presentation Layer 6 Presentation Layer 5 SessionLayer 5 Session Layer 4 TransportLayer 4 Transport Layer 3 NetworkLayer 3 Network Layer 2 Data Link Layer 2 Data Link 802.3802.3 Layer 1 Physical Layer 1 Physical 802.3802.3

802.3 Ethernet Frame Format802.3 Ethernet Frame Format

MACDestination

Address

MACSource

Address

CRCData + Padding

Bytes: 7 1 6 6 2

20 20 6-1460 4

IP TCP

Duplex: We're not talking apartments Duplex: We're not talking apartments

SimplexSimplexOnly one node can talk (one way traffic)Only one node can talk (one way traffic) Commercial Radio StationCommercial Radio Station

Half DuplexHalf DuplexOnly one node can talk at a timeOnly one node can talk at a time Walkie-TalkieWalkie-Talkie

Full DuplexFull DuplexBoth nodes can talk at same timeBoth nodes can talk at same time TelephoneTelephone

802.3 Flow Chart (NIC)802.3 Flow Chart (NIC)

Packet to Send?

No

Yes

Set Collision Couter= 0

Traffic on Network?

Yes

No

Send Packet Collision?

No

JamYes

Bump CollisionCounter by +1

16th Collision?

Drop Packet.Notify Higher Layer

Yes

Back-Off

No

802.3 Back-Off Algorithm802.3 Back-Off Algorithm choose random numberchoose random number

1st Collision1st Collision 0, 10, 12nd Collision2nd Collision 0, 1, 2, 30, 1, 2, 33rd Collision3rd Collision 0, 1, ..., 6, 70, 1, ..., 6, 74th Collision4th Collision 0, 1, ..., 14, 150, 1, ..., 14, 15

10th Collision10th Collision 0, 1, ..., 1022, 10230, 1, ..., 1022, 1023

15th Collision15th Collision 0, 1, ..., 1022, 10230, 1, ..., 1022, 102316th Collision16th Collision PuntPunt

Wait (Random Number*.0000512) secondsWait (Random Number*.0000512) seconds

10Base5 & 10Base2 (Obsolete)10Base5 & 10Base2 (Obsolete)

PC PC Printer

Logical & Physical BusAll nodes monitor traffic

Nodes share 10 Mbps

Coax Cable

10Base5 "Vampire Tap"10Base2 "T" connection

Images from Wikipedia

10BaseT & Shared Hub10BaseT & Shared Hub

PC

PC

PC

PC

Hub

Logical Bus & Physical StarShared hub (OSI Level 1) copies input bits to all outputs.

All nodes monitor traffic.

10BaseT & Shared Hub10BaseT & Shared Hub

PC

PC

PC

PC

Hub

Logical Bus & Physical StarEach PC gets 2.5 Mbps on average.

Twisted PairCabling

10BaseT & Switched Hub10BaseT & Switched Hub

PC

PC

PC

PC

SwitchedHub

Logical Bus & Physical StarSwitched Hub (OSI Level 1 & 2) copies packet to proper output.

Only the destination monitors traffic.


PC

PC

PC

PC

SwitchedHub

Logical Bus & Physical StarThis system can move up to 20 Mbps


PC

PC

PC

PC

SwitchedHub

Logical Bus & Physical Star

Each node shares 10 Mbps with the Switched Hub.


PC

PC

PC

PC

SwitchedHub

Using Half Duplex 10BaseT,a collision occurs if PC & Switched Hub

simultaneously transmit.

reception isscrewed up

Full Duplex SystemFull Duplex System

PC

PC

PC

PC

SwitchedHub

All 10 Gbps, most 1 Gbps, & many 100 Mbps systems are Full Duplex.

NIC’s are designed to simultaneously transmit & receive.Line no longer shared. No Collisions. No need for CSMA/CD.

Campus Network 1993Campus Network 1993

Ethernet Switched HubsEthernet Switched Hubs On Power Up know nothingOn Power Up know nothing When a packet arrives at an input port...When a packet arrives at an input port...

Look-Up Table consultedLook-Up Table consulted Source MAC address not in table?Source MAC address not in table?

Table Updated: MAC address & Port matchedTable Updated: MAC address & Port matched

Destination MAC address not in table?Destination MAC address not in table? Packet broadcast to all outputs (a.k.a. flooding)Packet broadcast to all outputs (a.k.a. flooding)

Desination MAC address in table?Desination MAC address in table? Packet shipped to proper outputPacket shipped to proper output

Ethernet Switched HubsEthernet Switched Hubs Look-up Table updated as packets arriveLook-up Table updated as packets arrive

Ethernet MAC Address : Port #Ethernet MAC Address : Port # Flooding does not scale well on WANFlooding does not scale well on WAN

OK on LAN with a probably a few hundred OK on LAN with a probably a few hundred addressesaddresses

Too much unnecessary traffic on WAN with millions Too much unnecessary traffic on WAN with millions of addressesof addresses

Ethernet is making way into MAN & WANEthernet is making way into MAN & WAN Requires modified protocolsRequires modified protocols

Ethernet FlavorsEthernet Flavors

802.3 10 Mbps802.3 10 Mbps 802.3u 100 Mbps (Fast Ethernet)802.3u 100 Mbps (Fast Ethernet) 802.3z 1 Gbps Ethernet802.3z 1 Gbps Ethernet 802.3ae 10 Gbps Ethernet802.3ae 10 Gbps Ethernet 802.3ba 40 & 100 Gbps Ethernet802.3ba 40 & 100 Gbps Ethernet

Shared EthernetShared Ethernet

TrunksAccess Lines

Hub

PC

PC

PC

PC

PC

PC

PC

PC

PC

All nodes share the system's 10 Mbps.Multiple paths = feedback loop = mess.

Hub

Hub

Hub

Switched EthernetSwitched Ethernet

TrunksAccess Lines

SwitchedHub

PC

PC

PC

PC

PC

PC

PC

PC

PC

Each node shares 10 Mbps with its switch.Network can move > 10 Mbps at any instant.Multiple paths usually not used.

SwitchedHub

SwitchedHub

SwitchedHub

Ethernet & Switched HubEthernet & Switched Hub

PC

PC

PC

Server

SwitchedHub

10/100 Mbps1 Gbps10 Gbps

Different speeds are used for different connections.

Server Server

PCPC

To therest of the

world.

Two Types of AddressesTwo Types of Addresses

MACDestination

Address

MACSource

Address

CRCData + PaddingIP TCP

Link TransmitterLink Receiver

Information Source Information Sink (Destination)

Local (Layer 2 MAC)Local (Layer 2 MAC) End-to-End (Layer 3 IPv4)End-to-End (Layer 3 IPv4)

Exception: NAT

Whose Address goes where?Whose Address goes where? Generally, PC's don't directly connect to RouterGenerally, PC's don't directly connect to Router

Usually connected to Switched Hub Usually connected to Switched Hub Using Using IPCONFIG /ALLIPCONFIG /ALL ... ...

Ethernet MAC address (hard-wired)Ethernet MAC address (hard-wired) 00 50 04 C1 73 50 (6 Bytes, Base 16)00 50 04 C1 73 50 (6 Bytes, Base 16) Last byte is 0101 0000Last byte is 0101 0000

Alpha-Numeric IP Address (usually fixed)Alpha-Numeric IP Address (usually fixed) es303f-2es303f-2.ceat.okstate.edu.ceat.okstate.edu host namehost name - network name - network name

Domain Name ServerDomain Name Server Converts alpha-numeric IP address to numericConverts alpha-numeric IP address to numeric

Whose Address goes where?Whose Address goes where? Numeric IP Address (assigned on Power Up)Numeric IP Address (assigned on Power Up)

Dynamic Host Configuration Protocol (DHCP)Dynamic Host Configuration Protocol (DHCP) 139.78.79.157 (4 Bytes, Base 10) on 31 Jan 2004139.78.79.157 (4 Bytes, Base 10) on 31 Jan 2004

Default Gateway (assigned on Power Up)Default Gateway (assigned on Power Up) Dynamic Host Configuration Protocol (DHCP)Dynamic Host Configuration Protocol (DHCP) 139.78.79.254 Router IP Address139.78.79.254 Router IP Address Where to send packets when destination not part of your Where to send packets when destination not part of your

networknetwork ceat.okstate.educeat.okstate.edu

Generally, Router sets the network boundaryGenerally, Router sets the network boundary

Packet to Print? Must know destination IP Address

Packet to Print? Must know destination IP Address

At my computer's IP Layer...At my computer's IP Layer... Adds 20B IP Header to each packetAdds 20B IP Header to each packet

Source IP address = My computerSource IP address = My computer(Terminating) Destination IP address = Printer(Terminating) Destination IP address = Printer

Is Information Sink IP address on my network?Is Information Sink IP address on my network?Yes? Tell Layer 2 to use Yes? Tell Layer 2 to use

Information Sink's MAC addressInformation Sink's MAC addressNo? Tell Layer 2 to use Router's MAC AddressNo? Tell Layer 2 to use Router's MAC Address

Shared 802.3 EthernetShared 802.3 Ethernet

TrunksAccess Lines

HubHub

HubHub

PC

PC

PC

PC

PC

Pr

PC

PC

PC

10 Nodes Share 10 MbpsPrinter part of "ceat.okstate.edu".

R

Whose address goes where?Whose address goes where?

MACDestination

Address

MACSource

Address


PC MACPrinter MAC

Information Source (PC IP) Information Sink (Printer IP)

Hub ignores packet contents, copies bits to all outputs.

Shared 802.3 EthernetShared 802.3 Ethernet

Trunks

HubHub

HubHub

PC

PC

PC

PC

PC

Pr

PC

PC

PC

All nodes will see packets from PC to Printer.

R


TrunksAccess Lines

PC

PC

PC

PC

PC

PC

PC

SwitchedHub

SwitchedHub

SwitchedHub

PC

Pr

RSwitched

Hub

Packet formatting same as before.Only the Printer will see packets from the PC.


TrunksAccess Lines

PC

PC

PC

PC

PC

PC

PC

Packets need to cross a network boundary.

SwitchedHub

SwitchedHub

PC

Pr

R

SwitchedHub


MACDestination

Address

MACSource

Address


PC MACRouter MAC


Connection from PC to Router

IP addresses don't match MAC addresses.


MACDestination

Address

MACSource

Address


Router MACPrinter MAC


Connection from Router to Printer


MACDestination

Address

MACSource

Address


MAC addresses change when router crossed.Stay same through an Ethernet Switch.

IP addresses remain unchanged end-to-end.

Frame RelayFrame Relay Early ‘90’s technologyEarly ‘90’s technology Covers OSI Layer 2Covers OSI Layer 2 N*64 Kbps or N*1.54 Mbps connectionsN*64 Kbps or N*1.54 Mbps connections Virtual CircuitsVirtual Circuits

Route once on circuit set up.Route once on circuit set up. Packet Switch, StatMux BackbonesPacket Switch, StatMux Backbones Accessed by Routers with proper interfaceAccessed by Routers with proper interface Being replaced by the InternetBeing replaced by the Internet

Frame Relay BackboneFrame Relay Backbone

FR Switch

TrunksLeased Line

Frame Relay ‘Cloud’Trunk capacity shared via StatMux & Packet Switching


FR Switch

TrunksLeased Line

Corporate Routers or FRAD's usually attached to FR backbones.

Corp.LAN

Corp.LAN

ISO OSI Seven Layer ModelFrame Relay Switch (Layer 1 & 2)ISO OSI Seven Layer ModelFrame Relay Switch (Layer 1 & 2)

Layer 7 ApplicationLayer 7 Application Word PerfectWord Perfect Layer 6 Presentation Layer 6 Presentation Windows APIWindows API Layer 5 SessionLayer 5 Session TCP, WindowsTCP, Windows Layer 4 TransportLayer 4 Transport TCP, WindowsTCP, Windows Layer 3 NetworkLayer 3 Network IP, WindowsIP, Windows Layer 2 Data LinkLayer 2 Data Link Frame Relay, Frame Relay,

T Carrier or SONETT Carrier or SONET Layer 1 PhysicalLayer 1 Physical T Carrier T Carrier or SONETor SONET

Frame Relay Packet Format(Assuming Ethernet LAN)

Frame Relay Packet Format(Assuming Ethernet LAN)

Data

3 20 20 0-1460 3

IP TCPFR Header

FR Trailer

Header includes 10 bit DLCI Locally Unique Address (Valid between I/O ports)

Trailer includes 2 byte Frame Check Sequence Only checks for errors in FR header TCP error checking should catch any payload error

LAN #1

PC

Server

Frame Relay ConnectivityFrame Relay Connectivity

FR Switch

VC #2

Suppose we need to connect to three LAN's.

Server

VC #1

LAN #2

LAN #3

Frame Relay VC Set UpFrame Relay VC Set Up Client requests connectivity from CarrierClient requests connectivity from Carrier Carrier arranges for Leased Line to nearest Point of PresenceCarrier arranges for Leased Line to nearest Point of Presence Technician runs Routing Algorithm on a Work StationTechnician runs Routing Algorithm on a Work Station

Paths through network generatedPaths through network generated Appropriate Switches NotifiedAppropriate Switches Notified

DLCI's AssignedDLCI's AssignedI/O mappings updated in Switch Look-Up TablesI/O mappings updated in Switch Look-Up Tables

Source Router ships Source Router ships allall FR traffic down same leased line FR traffic down same leased line FR switches use DLCI to properly outputFR switches use DLCI to properly output

Note LAN #2 & #3 can communicate with each other thru edge Note LAN #2 & #3 can communicate with each other thru edge router of LAN #1router of LAN #1

LAN

PC

LAN

Server


FR Switch

Look Up tables mapInput DLCI and Port toOutput DLCI and Port. Reverse path DLCI's not shown.

LAN

Server

DLCI 375DLCI 177

DLCI 177

DLCI 526

DLCI 617

DLCI 375

Moving PacketsPC1 > Ethernet (Switched) Hub > Router1 > FR1 > FR2 > Router2 > Ethernet (Switched) Hub > Server


PC1 injects Ethernet PacketPC1 injects Ethernet Packet Destination IP Address of Server (info sink)Destination IP Address of Server (info sink) Router Ethernet MAC AddressRouter Ethernet MAC Address

Router1Router1 Examines, processes, strips off Ethernet HeaderExamines, processes, strips off Ethernet Header Examines Destination IP Address & Routing Table Examines Destination IP Address & Routing Table Sees best path is over FR networkSees best path is over FR network

Router1 injects FR PacketRouter1 injects FR Packet DLCI 375 carrying Layer 3-7 infoDLCI 375 carrying Layer 3-7 info

LAN

PC

LAN

Server


12

FR Switch

1

Look Up tables mapInput DLCI and Port toOutput DLCI and Port.

LAN

Server

2DLCI 375



FR Switch 1FR Switch 1 Examines FR Look Up TableExamines FR Look Up Table DLCI 375 on input from Router1 maps toDLCI 375 on input from Router1 maps to

DLCI 177 on output to FR Switch 2DLCI 177 on output to FR Switch 2 FR Switch 1 injects FR packetFR Switch 1 injects FR packet

DLCI 177 carrying Layer 3-7 infoDLCI 177 carrying Layer 3-7 info

LAN

PC

LAN

Server


FR Switch


LAN

Server

DLCI 177

12

1 2



FR Switch 2FR Switch 2 Examines FR Look Up TableExamines FR Look Up Table DLCI 177 on input from Switch1 maps toDLCI 177 on input from Switch1 maps to

DLCI 177 on output to Router2DLCI 177 on output to Router2 FR Switch 2 injects FR packetFR Switch 2 injects FR packet

DLCI 177 carrying Layer 3-7 infoDLCI 177 carrying Layer 3-7 info

LAN

PC

LAN

Server


FR Switch


LAN

Server

DLCI 177

12

1 2



Router 2Router 2 Strips off FR HeaderStrips off FR Header Examines Destination IP Address Examines Destination IP Address

& Routing Table& Routing Table Sees best path is over Internal LANSees best path is over Internal LAN

Router 2 injects Ethernet PacketRouter 2 injects Ethernet Packet Server Ethernet MACServer Ethernet MAC

(Assuming Server is on same subnet as Router)(Assuming Server is on same subnet as Router)

ATMATM Mid ‘90’s technologyMid ‘90’s technology Covers OSI Layer 2, Line Speeds Covers OSI Layer 2, Line Speeds << OC-48 OC-48 Virtual CircuitsVirtual Circuits

Route once on circuit set up.Route once on circuit set up. Five classes of serviceFive classes of service Cell Switch (53 bytes), StatMux or TDMCell Switch (53 bytes), StatMux or TDM Failed at desktopFailed at desktop

OK on Carrier WAN OK on Carrier WAN & Corporate Backbone& Corporate Backbone

Fading from the sceneFading from the sceneBeing replaced by InternetBeing replaced by Internet

ISO OSI Seven Layer ModelATM SwitchISO OSI Seven Layer ModelATM Switch

Layer 7 ApplicationLayer 7 Application Word PerfectWord Perfect Layer 6 Presentation Layer 6 Presentation Windows APIWindows API Layer 5 SessionLayer 5 Session TCP, WindowsTCP, Windows Layer 4 TransportLayer 4 TransportTCP, WindowsTCP, Windows Layer 3 NetworkLayer 3 Network IP, WindowsIP, Windows Layer 2 Data LinkLayer 2 Data LinkATM, ATM, SONETSONET

or T Carrier or T Carrier Layer 1 PhysicalLayer 1 Physical T Carrier,T Carrier,

or SONET or SONET

ATM Cell #1 Format AAL5 ATM Cell #1 Format AAL5

Data

5 20 20 8

IP TCPATM Header

Header includes 24 or 28 bit VPI & VCIFollow on cells carry remainder of the packet.

LAN

LAN

Carrier ATM NetworkCarrier ATM Network

What appears to be nailed up end-to-end connectivity (a Virtual Circuit). Switch I/O mappings similar to Frame Relay.

ATM SwitchATM Switch

OC-48TrunksLeased Line

OC-1

OC-1

StatMuxATM VersionStatMuxATM Version

frequency

tim

e

1

1

3

1

Different channels use all of the frequency some of the time,at random, as needed.

empty cell

empty cell

Canalsouse

TDM.

2

802.3LAN

LAN

OSU Campus Network ('95 - '01)OSU Campus Network ('95 - '01)


OC-3, thenOC-12Trunks

OneNet

ATM-EthernetATM-EthernetSwitchSwitch

802.3LAN

802.3LAN

LAN

LAN

ATM NetworkATM Network

All kinds of boxes aretypically hanging off carrier ATM Switches.


TrunksAccess Line

Frame RelayRouters

ATM PVC Set UpATM PVC Set Up Client requests connectivity from CarrierClient requests connectivity from Carrier Carrier arranges for Leased Line to nearest Point of PresenceCarrier arranges for Leased Line to nearest Point of Presence Technician runs Routing Algorithm on a Work StationTechnician runs Routing Algorithm on a Work Station

Paths through network generatedPaths through network generated Appropriate Switches NotifiedAppropriate Switches Notified

VPI's and VCI's AssignedVPI's and VCI's AssignedI/O mappings updated in Switch Look-Up TablesI/O mappings updated in Switch Look-Up TablesSwitch Resources reserved, depending on CoS requestedSwitch Resources reserved, depending on CoS requested

Corporate ATM switch (or Router with a plug-in ATM compatible Corporate ATM switch (or Router with a plug-in ATM compatible card) ships card) ships allall traffic down same leased line traffic down same leased line ATM switches use VPI & VCI to properly outputATM switches use VPI & VCI to properly output

ATM Connection Admission Control

ATM Connection Admission Control

Procedure for setting up VC’sProcedure for setting up VC’s End user requests call set-upEnd user requests call set-up

Provides destination, CoS, parametersProvides destination, CoS, parameters Switches determine if resources areSwitches determine if resources are

availableavailableSufficient Buffer Space?Sufficient Buffer Space?Sufficient unreserved trunk bandwidth?Sufficient unreserved trunk bandwidth?

Call is rejected if insufficient resourcesCall is rejected if insufficient resources

ATM Connection Admission ControlATM Connection Admission Control CBR VC’sCBR VC’s

Reserve Peak Trunk BW Reserve Peak Trunk BW Reserve Minimal Buffer SpaceReserve Minimal Buffer Space

VBR VC’sVBR VC’s Reserve Average Trunk BWReserve Average Trunk BW Reserve Buffers to cover burstsReserve Buffers to cover bursts

ABR VC’sABR VC’s Reserve Minimum Trunk BWReserve Minimum Trunk BW Reserve Buffers to cover burstsReserve Buffers to cover bursts

UBR VC’sUBR VC’s Reserve NothingReserve Nothing Allow VC establishment if spare BW & Buffers Allow VC establishment if spare BW & Buffers

above some minimum above some minimum

The InternetThe Internet

VASTVAST collection of interconnected collection of interconnected networks networks

Mid ‘70’s technologyMid ‘70’s technology Key Building Block:Key Building Block:

Routers running IP (Layer 3)Routers running IP (Layer 3) Packet Switch, StatMuxPacket Switch, StatMux Designed for dataDesigned for data

Internet Service Provider BackboneInternet Service Provider Backbone

Packet Switched Statmux Network.Full duplex trunks.

Router

TrunksAccess Line

Wash

ington

D.C

. Area - 2000

Wash

ington

D.C

. Area - 2000

ISO OSI Seven Layer ModelIP RouterISO OSI Seven Layer ModelIP Router

Layer 7 ApplicationLayer 7 Application Word PerfectWord Perfect Layer 6 Presentation Layer 6 Presentation Windows APIWindows API Layer 5 SessionLayer 5 Session TCP, WindowsTCP, Windows Layer 4 TransportLayer 4 Transport TCP, WindowsTCP, Windows Layer 3 Network Layer 3 Network IPIP, Windows, Windows Layer 2 Data LinkLayer 2 Data Link Ethernet, Ethernet, FRFR, , ATMATM

SONET, OTN, T-Carrier, PPP, WiFiSONET, OTN, T-Carrier, PPP, WiFi Layer 1 PhysicalLayer 1 Physical Ethernet, SONET, Ethernet, SONET,

OTN, T-Carrier, DSL, Cable Modem, WiFiOTN, T-Carrier, DSL, Cable Modem, WiFi

LAN

LAN

LAN

Internet Service Provider NetworkInternet Service Provider Network

Corporate Routers & Other ISP Routers attached.ISP trunks could be...

RouterRouter

TrunksLeased Line

T1

T1

Leased LinesLeased Lines

Nailed up end-to-end connectivity (a Circuit).Bit pipe. No packet processing between Routers.


TrunksLeased Line

ISPRouter

ISPRouter

Light Path (Wave) Connectivity (OC-48, OC-192, or OC-768)

Light Path (Wave) Connectivity (OC-48, OC-192, or OC-768)

Nailed up end-to-end connectivity (a Circuit).Light Path. No packet processing between Routers.

Optical SwitchOptical Switch

TrunksFiber

ISPRouter

ISPRouter

Internet Packet FormatInternet Packet Format

Traffic

?? 20 20 0-1460 ??

IP TCPLayer 2 Header

Layer 2 Trailer?

Probably originated on an Ethernet.

InternetInternet Router Line Speeds generallyRouter Line Speeds generally

T1 to OC-768 on the WAN, some 100 Gbps T1 to OC-768 on the WAN, some 100 Gbps (Mostly Leased Line or Light Waves)(Mostly Leased Line or Light Waves)

10/100/1,000/10,000 Mbps (Ethernet) on the LAN10/100/1,000/10,000 Mbps (Ethernet) on the LAN Some Ethernet making it into MAN Some Ethernet making it into MAN

Hierarchical Alpha-Numeric NamesHierarchical Alpha-Numeric [email protected]@machine.institution.domain

DatagramsDatagrams Independent I/O decisions on every packet Independent I/O decisions on every packet Not guaranteed to follow same pathNot guaranteed to follow same path

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