Computer Networks (ComNet) 1/5 : Introductionfourmaux/ARes/ARes_C1_en_4.pdf · 2019-10-03 · O....

Course presentationAdministrative questions

Course introduction

Computer Networks (ComNet)1/5 : Introduction

O. Fourmaux - T. Friedman

Version 8.0

O. Fourmaux - T. Friedman Computer Networks (ComNet) 1/5 : Introduction


Course introduction

ComNet: course 1/5 outline

1 Course presentationCourse objectivesPedagogical approachInstructional methodology

2 Administrative questionsScheduleEvaluation

3 Course introductionNetwork componentsProtocol hierarchyTCP/IP example



Course introduction

Course objectivesPedagogical approachInstructional methodology







Course introduction


Reinforce your understanding of networking

Deepen and extend beyond a first course in networking

example: Network introduction course from the S.U. Licenceprerequisites, both theoretical and technical:

the vocabularyintroduction to signal processingbasic protocol mechanismsclassical protocols (HDLC, IP, routing, UDP, TCP)ISO layered model



Course introduction


Understand fundamental technologies

Study the principal current network architecture and itsenvironment à TCP/IP and Internet

standardized applications (web, DNS, e-mail, multimedia, . . . )dynamic mechanisms (congestion control, . . . )IPv4/v6 adressing (multicast, DHCP, NAT, tunnels, . . . )advanced routing (AS hierarchy, OSPF, BGP, . . . )media architectures (Ethernet, ADSL, FTTH, . . . )



Course introduction


Basis for further courses in networking

Prerequisite for advanced networking courses

In M1-S2: for required courses for students in the networkingspeciality, and for elective courses for other students

mobility, autonomous, wireless à U.E. WiMOBadvanced routing à U.E. iROUT

In M2-S3: for students in the networking specialitytraffic engineering and quality of service à U.E. ITQoSnetwork data analysis à U.E. NDAnetwork metrology à U.E. NETMETnetwork evolution with virtualization and automation à U.E.NEVAnetwork security à U.E. SECRESsmart mobility systems à U.E. SMS



Course introduction


Course content

Top down approach:

Part 1/5 IntroductionPart 2/5 Application: remote login, file transfert...

... multimedia, DNS, SNMP.Part 3/5 Transport: services, UDP and TCP examples,

... congestion control, DCCP, SCTP, QUIC.Part 4/5 Network: IPv4/v6, multicast, NAT...

... hierarchical routing, OSPF and BGP.Part 5/5 Link: Switched Ethernet,

... point-to-point, local loop.



Course introduction


Labs

Four-hour labs consisting of written exerices (TDs) and practicalones (TMEs):

interlacing of theoretical and practical aspectsillustrated by concrete examples on a networking testbed usingreal hardware:

(Standard conf.)

SwitchX 16

(Network conf.)

X 16

server PC

control console

probe PC

Router

client PC

PC PPTI PC PPTI

powermanager

Internet

via PPTI

Internet

via PPTI



Course introduction


Lab schedule (tentative)

week content lab1 Introduction to the networking testbed n°12 Applications (1): Telnet, FTP, and web analysis n°23 Applications (2): SMTP, DNS, and SNMP analysis n°34 Completion of previous weeks’ labs5 Transport (1): analysis of mechanisms n°46 Review/completion of previous weeks’ labs7 Transport (2): congestion control (planetlab) n°58 Network (1): IP/ICMP (begin) n°69 Network (2): IP/ICMP (end) n°610 Review/completion of previous weeks’ labs



Course introduction


Course organization

10 weeks, within which. . .Lectures: 10 × 2 hrs

T. Friedman, O. FourmauxLabs: 10 × 4 hrs

T. Friedman, O. Fourmaux

Course website:Information and updates:http://www-rp.lip6.fr/~fourmaux/index-cours.html



Course introduction


Networking testbed for the labs

The testbed hardware rack, located in theM2-RES computer lab, room 14-15:503

Each pair of students has access to:a classical PPTI host machinededicated hardware for configuringnetworks, and capturing and analyzingtraffic:

1 Cisco switch1 Cisco router3 VMs in on 1U rackable server



Course introduction


Supporting traces and documents

Network traffic traces, on which to test your knowledgegenerated on the networking testbed during the labsgenerated by the students (on the testbed or elsewhere)pre-recorded (to use in case the testbed is down, or you wishto work elsewhere), available here:http://www-rp.lip6.fr/~fourmaux/Traces/labV6.html

Documents available on the course website:course slideslab handouts (including optional exercises)past exams

Textbooksavailable in the Mathematics & Computer Science librariehttp://www.bupmc.upmc.fr/fr/labupmc/horaires.html


http://www-rp.lip6.fr/~fourmaux/index-cours.html

http://www-rp.lip6.fr/~fourmaux/Traces/labV6.html

http://www.bupmc.upmc.fr/fr/labupmc/horaires.html


Course introduction


Bibliography

James F. Kurose, Keith W. Ross

Computer Networking: A Top-down Approach Featuringthe Internet, 7th edition (Pearson, 2016)

Andrew S. Tanenbaum, David J. Wetherall

Computer Networks, 5th edition (Prentice Hall, 2011)

Douglas Comer

Internetworking with TCP/IP Vol 1: Principles, Protocolsand Architectures, 6th edition (Prentice Hall, 2013)

Olivier Bonaventure

Computer Networking: Principles, Protocols andPractice, http://inl.info.ucl.ac.be/CNP3



Course introduction

ScheduleEvaluation







Course introduction

ScheduleEvaluation

Tentative schedule for 2018-2019

dates lecture lab session comments16-20/9 1 123-27/9 2 2

30/9-4/10 3 37-11/10 4 414-18/10 5 521-25/10 6 68/11 – – midterm exam (to confirm)

18-22/11 7 725-29/11 8 82-6/12 9 99-13/12 10 1013/1 – – final exam (to confirm)8/6 – – makeup exam (to confirm)

Warning : labs week = lecture week



Course introduction

ScheduleEvaluation

Weekly schedule

8h30-10h30 10h45-12h45 13h45-15h45 16h00-18h00Monday Lecture (Fr)

Amphi 15Tuesday Lab G1 (ITESCIA) Lab G2 (AFTI)

14-15:503 14-15:503Wednesday Lab G3

14-15:503Thursday Lab G4 Lab G5

14-15:503 14-15:503Friday Lecture (En) Lab (En)

24-25:105 14-15:503


http://inl.info.ucl.ac.be/CNP3

14-15:503

14-15:503

14-15:503

14-15:503

14-15:503

24-25:105

14-15:503


Course introduction

ScheduleEvaluation

Exam details

Three exams:Midterm exam (application and transport layers only)Final exam (the whole course)Makeup (the whole course)

Exam rulesno electronic equipment (mobile phone, calculator, etc.)no documents except one handwritten A4 page

Definitionhandwritten: entirely written by hand (no photocopies)



Course introduction

ScheduleEvaluation

Calculating the grade for the course

1st session: midterm and final examsNCOMNET1 = 0.4Nmidterm + 0.6Nfinal

Note: If you pass the course in the first session (NCOMNET1 > 50),you may not take the makeup exam.

2nd session: makeup (you didn’t pass the course in the 1st session)

If your grade is officially compensated for by passing grades inother courses: by default, you keep your gradeNCOMNET1 < 50

You may sit the makeup exam iff you explicitly sign up to doso with the RES secretariat

If your grade is not compensated for, you must take themakeup exam (if you do not, NCOMNET2 = 0)

NCOMNET2 = NmakeupO. Fourmaux - T. Friedman Computer Networks (ComNet) 1/5 : Introduction


Course introduction

ScheduleEvaluation

Final grade adjustments

Two weeks after the final exam (1st session) or the makeup exam(2nd session):

exams graded and a curve is appliedgrades posted on DBUFRstudents consult their graded examsjuries

course jury (determines passing or failing)Networking speciality jury (grade compensation)Masters program jury (final decision)



Course introduction

Network componentsProtocol hierarchyTCP/IP example







Course introduction


The environment we discuss in this lecture

The Internetomnipresent

heterogeneousevolvingcomplex. . .

à difficult tocharacterize!

Let’s look at anexample:



Course introduction


Internet components

What are the basic elements of the Internet?

communications linksrouters (packet forwarding)hosts (end systems):

Unix workstations

classical PCs

mobile phones

an Internet toaster(1990). . .

networked applicationscommunication protocols. . .



Course introduction


Protocols: analogy

Temps

Bonjour

Où est la gare ?

Demande d’ouverture

de connexion TCP

... ...

Bonjour établissement de la connexion

Deuxième rue à gauche Envoi de la page d’accueil

GET http://www.upmc.fr

Réponse positive et

��

��



Course introduction


Protocol: definition

DefinitionProtocol: protocols define format, order of messages sent andreceived among network entities, and actions taken upon messagetransmission and receipt.

Remarkany interaction between entities over the Internet isbased on protocols

this course focuses mainly on protocols

Examplesweb requestresolving name queries into IP addressesroute computationcongestion control. . .



Course introduction


Application services

Internet users use distributed applications:World Wide Webelectronic mailpeer-to-peer file sharingdistributed gamesaudio and video streamingreal-time audio and video. . .



Course introduction


Network services

Applications are based on two types of services:

connectionlessanalogy with the postal service

connection orientedanalogy with telephone service

and have correspondingly different characteristics:reliabilityorderingflow controlcongestion control. . .



Course introduction


Quality of service

Qualité de Service (QoS) in the Internet

The Internet offers a best effort serviceno guarantees; the main concern is connectivity!how many end-systems?

10× 109 connected devices ( most of the 3.0× 109 PCs +3.5× 109 smartphones. . .4.5× 109 users activeInternet traffic >>> telephone traffic

multimedia applications must adapt to the uncertainconditions. . .

à U.E. CONT / U.E. ITQoS (M2-S3)



Course introduction


Internet standardisation

IESGIRSG

IETF

IRTF

ISOC

Working Areas Working Groups

Working Groups

... ...

... ... ...ISOC : Internet SOCiety

IAB : Internet Architecture Board

IRSG : Internet Research Steering Group

IRTF : Internet Research Task Force

IESG : Internet Engineering Steering Group

IETF : Internet Engineering Task Force

IAB

IETF (Internet Engineering Task Force) working groupsmore than 8650 RFCs (Requests For Comments)mostly de facto rather than de jure standards

IP, TCP, SMTP, SNMP, HTTP...http://www.rfc-editor.org/


http://www.rfc-editor.org/


Course introduction


Some websites

IETF (Internet Engineering Task Force),http://www.ietf.org/

ACM SIGCOMM (Association for Computing Machinery –Special Interest Group in Data Communication),http://www.sigcomm.org/

IEEE Communications Society, http://www.comsoc.org/IEEE Computer Society, http://www.computer.org/



Course introduction








Course introduction


Network edge



Course introduction


Network edge (abstraction)


http://www.ietf.org/

http://www.sigcomm.org/

http://www.comsoc.org/

http://www.computer.org/


Course introduction


Distributed applications

client/server model

Client process

Request

Reply

Server process

Client machine Server machine

Network

the client sends requestsreceives service from an always-on server

webe-mailDNS. . .

peer-to-peer modelminimal use of dedicated serverssymmetrical communication



Course introduction


Application protocols

Heterogeneous environment à standardised interactionsweb: HTTP, HTMLe-mail: SMTP, MIME, POP, IMAPremote access: Telnet, NVTfile transfer: FTPdirectory: DNSmanagement: SNMP, MIB

à Part 2/5: Applications



Course introduction


End-to-end services

Types of service that the network offers to end-hosts:

connection oriented servicereliabilityorderingflow controlcongestion control. . .

TCP

connectionless servicesimplebasis for other protocols

UDP



Course introduction


Impact of end-to-end control

What is the shape of traffic generated by TCP?

tcptahoe.seq

tcptahoe.cwnd

seq (Ko) / cwin (Ko/10)

t0.0000

100.0000

200.0000

300.0000

400.0000

500.0000

600.0000

700.0000

800.0000

0.0000 2.0000 4.0000 6.0000 8.0000 (s)

à Part 3/5: TransportO. Fourmaux - T. Friedman Computer Networks (ComNet) 1/5 : Introduction


Course introduction


Inside the network



Course introduction


Communication links

Physical mediamedia with waveguide

twisted pair (UTP5+, UTP6,. . . )coaxial cables (baseband, broadband,. . . )optical fibers (multimode, monomode,. . . )

media without waveguidesatellite links (geostationary, constellation, . . . )terrestrial links (radio-waves, micro-waves, infrared,optical,. . . )

Access technologyshared mediumframing

Intermediate elements. . .



Course introduction


Data forwarding

Circuit switching or packet switching?

(a)

(b)

Switching office

Physical copper connection set up when call is made

Packets queued up for subsequent transmission

Computer

Computer

pictures from Tanenbaum A. S. Computer Networks 3rd editionO. Fourmaux - T. Friedman Computer Networks (ComNet) 1/5 : Introduction


Course introduction


Virtual circuit transmission

21

32

3

(b)

1

3

(a)

(c)

(d)

2 1

32

1

pictures from Stallings W. High Speed Networks



Course introduction


Message transmission

(b)

(a)

(c)

(d)




Course introduction


Datagram transmission

21

3 2 1

3

(c)

3

1

2

(b)

(a)

(d)

2 1

3




Course introduction


Comparing the three types of transmission

Data

Pkt 1

Pkt 2

Pkt 3

Pkt 1

Pkt 2

Pkt 3

Pkt 1

Pkt 2

Pkt 3

A B C D

Msg

Msg

Msg

A B C DA B C D

Propagation delay

Queuing delay

Call request signal

Time spent

hunting for an

outgoing trunk

Call accept signal

AB trunk

BC trunk

CD trunk

(a) (b) (c)

Tim

e

pictures from Tanenbaum A. S. Computer Networks 3rd editionO. Fourmaux - T. Friedman Computer Networks (ComNet) 1/5 : Introduction


Course introduction


Delay recap

Types of delays in packet switching:nodal processing delay

uncompressible (Dn)queuing delay

depends on congestion (Dq = 0 if no congestion)transmission delay

depends on the size of the packet (Dt = L/R)propagation delay

v = 2.108m/s to 3.108m/s (Dp = d/v)

Formula for end-to-end delay?



Course introduction


Internet addressing

Packets travel from source to destination hop-by-hop, with anaddress-based forwarding decision made at each intermediate node(router).

IPv4/v6 protocol

universalvirtual addressingabstracts out the lower layer technologies

each technology provides encapsulationaddress conversion

Protocols have evolved to adapt to the present networkclassless addressing (CIDR), multicast, IPv6address translation (NAT)auto-configuration (DHCP)filtering. . .



Course introduction


Routing mechanisms

When and how to determine the route taken by data?

the type of path followed depends upon the type of network:initially

circuit switchingvirtual circuits

for each packetdatagram

calculating the informationrouting algorithmsrouting tables

local or centralizedstatic or dynamic

information exchangerouting protocols. . .



Course introduction


Routing in the Internet

Datagram networkrouting of each packet

Hierarchical structure of the network (ASes)internal routing: OSPFexternal routing: BGP

à Part 4/5: Network



Course introduction


Network core



Course introduction


Ethernet technology

VLAN 2

VLAN 1

VLAN 1

VLAN 3

VLAN 3

VLAN 1

VLAN 1

VLAN 1

100 Mbps 100 Mbps

100 Mbps

1 Gbps

1 Gbps

1 Gbps

1 Gbps

10 Gbps

10 Gbps10 Gbps

10 Gbps

1 Gbps

VLAN 1VLAN 2VLAN 3

SwitchEthernet

SwitchEthernet

SwitchEthernet

SwitchEthernet

SwitchEthernet

CiscoSystems Cisco 7000 SERIES

LAN evolution towards the WAN with Fast Ethernet, GigabitEthernet, 10Gigabit Ethernet and 100Gigabit Ethernet.Integrating switching and structuring through VLANs. . .à Part 5/5 (1): Ethernet



Course introduction


MPLS technology

SwitchEthernet





Integrating switching mechanisms at the network level (ATM,MPLS,. . . ).à U.E. RTEL (M1-S1)



Course introduction


Point-to-point technology

TCP/IP connectionusing PPP

PPP only for old serial connections?PPP over SONET: POSPPP over Ethernet: PPPoEPPP over ATM: PPPoAPPP over IP: L2TP . . .

à Part 5/5 (2): Point-to-point



Course introduction


Access networks



Course introduction


Entreprise networks

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Course introduction


Wired residential

Copper twisted pair

Switch

Switching office

High-bandwidth fiber trunk

Junction box

(a)

(b)

House

High-bandwidth fiber trunk

Copper cable TV wire

House

Junction box

Fiber

Fiber

Residential (PSTN/ADSL, cable, optical fiber,. . . )à Part 5/5 (3): Local loop



Course introduction


Wireless access and mobility

Depending upon the degree of mobility:micro-mobility

Bluetooth/WPAN (IEEE 802.15)wireless local network

Wi-Fi/WLAN (IEEE 802.11)wireless metropolitan network

BLR/WMAN (IEEE 802.16)mobile phone

GSM, CDMA, GPRS, EDGECDMA 2000, UMTS, WCDMA, HSPA+LTE, WiMAX, LTE AdvancedIMTS-2020, LTE-B...

à U.E. WiMOB (M1-S2)



Course introduction








Course introduction


Protocols, layers, and interfaces

Layer 5

Layer 4

Layer 3

Layer 2

Layer 1

Host 1

Layer 4/5 interface

Layer 3/4 interface

Layer 2/3 interface

Layer 1/2 interface

Layer 5 protocolLayer 5

Layer 4

Layer 3

Layer 2

Layer 1

Host 2

Layer 4 protocol

Layer 3 protocol

Layer 2 protocol

Layer 1 protocol

Physical medium

picture from Tanenbaum A. S. Computer Networks 3rd edition



Course introduction


Anthropological analogy

I like rabbits

Location A

3

2

1

3

2

1

Location B

Message Philosopher

Translator

Secretary

Information for the remote translator

Information for the remote secretary

L: Dutch Ik hou van konijnen

Fax #--- L: Dutch Ik hou van konijnen

J'aime les

lapins

L: Dutch Ik hou van konijnen

Fax #--- L: Dutch Ik hou van konijnen




Course introduction


Repeated encapsulation

H2 H3 H4 M1 T2 H2 H3 M2 T2 H2 H3 H4 M1 T2 H2 H3 M2 T2

H3 H4 M1 H3 M2 H3 H4 M1 H3 M2

H4 M H4 M

M M

Layer 2 protocol

2

Layer 3 protocol

Layer 4 protocol

Layer 5 protocol

3

4

5

1

Layer

Source machine Destination machine




Course introduction


OSI (Open Systems Intercon. Reference Model – 1983)Layer

Presentation

Application

Session

Transport

Network

Data link

Physical

7

6

5

4

3

2

1

Interface

Interface

Host A

Name of unit exchanged

APDU

PPDU

SPDU

TPDU

Packet

Frame

Bit

Presentation

Application

Session

Transport

Network

Data link

Physical

Host B

Network Network

Data link Data link

Physical Physical

Router Router

Internal subnet protocol

Application protocol

Presentation protocol

Transport protocol

Session protocol

Communication subnet boundary

Network layer host-router protocol

Data link layer host-router protocolPhysical layer host-router protocol



Course introduction


TCP/IP reference model (1974)

TCP/IPOSI

Application

Presentation

Session

Transport

Network

Data link

Physical

7

6

5

4

3

2

1

Application

Transport

Internet

Host-to-network

Not present in the model




Course introduction


TCP/IP: comparison

Firmware

Software

OperatingSystem

UserSpace

Hardware

Physical

NetworkAccess

Internet

Application

Transport(host−to−host)

TCP/IP

Application

Presentation

Session

Transport

Network

Data Link

Physical

OSI

these pictures and to the end are from Stallings W. High Speed Networks



Course introduction








Course introduction


TCP/IP: example

Server

FrameRelay

Network

Router

IEEE 802 LAN

Workstation

Physical

MAC

LLC

IP

Physical

MAC

LLC

IP

Physical

FrameRelay

FrameRelay

TCP

Application

Physical

IP

TCP

Application



Course introduction


TCP/IP: concept

Router J

TCP

IP

Physical Physical

IP

NAP 1 NAP 2

Network AccessProtocol #1

Host A

App XApp Y

TCP

IP

Network AccessProtocol #2

Host B

App YApp X

Network 1 Network 2

Global networkaddress

Subnetwork attachmentpoint address

Logical connection(e.g., virtual circuit)

Logical connection(TCP connection)

Port orservice access point (SAP)



Course introduction


TCP/IP: sender actions

DataTI

DataT

Data

Physical

IP

TCP

Application

FrameRelay

DataTIF F



Course introduction


TCP/IP: router actions

DataTIL

Physical

MACDataTILM MDataTIF F

LLC

FrameRelay

DataTI

IP

Physical



Course introduction


TCP/IP: receiver actions

DataTIL

Physical

LLC

IP

TCP

MAC

Data

Application

DataTI

DataT

DataTILM M


Computer Networks (ComNet) 1/5 : Introductionfourmaux/ARes/ARes_C1_en_4.pdf · 2019-10-03 · O....

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Transcript of Computer Networks (ComNet) 1/5 : Introductionfourmaux/ARes/ARes_C1_en_4.pdf · 2019-10-03 · O....