CSE 422Computer Networks

Dr. Abdol-Hossein Esfahanian

Computer Science and Engineering Department

3115 Engineering Building

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Catalog DescriptionCSE 422:  Computer Networks Prerequisite: (STT 351 or ECE 280) and (CSE 320 or ECE 331) and (CSE 410 or concurrently)Description: Computer network architectures and models. Physical media and signaling. Data link protocols. Medium access control. Routing and IP. Transport services including TCP/UDP. Network applications. Local-area and wide-area networks.

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Course ObjectivesLearn the fundamentals of computer networking.

Understand how these fundamentals are applied in real networks, in particular, the Internet.

Understand the relationship between theory and practical design issues in network hardware and software.

Gain an in-depth understanding of how network applications software is supported by underlying protocols.

Learn that computer networks evolve.

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Course OutlineIntroductionOverview of computer networksNetwork architecture modelsNetwork programming interfaces

Physical LayerServices provided to the data link layerTheoretical basis for data communicationBandwidth limitationsAnalog and digital transmissionTransmission mediaSignaling methodsMultiplexing and switchingWireless/Mobile communication

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Course Outline …Data Link Layer Services provided to the network layer Error detection and correction Stop-and-wait protocols Sliding window protocols

Medium Access Sublayer Channel allocation problems Contention-based protocols Ethernet architecture 802.x protocols

Network Layer Services provided to the Transport layer Routing algorithms Internetworking Internet Protocol

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Course Outline…Transport LayerServices provided to the upper layersConnection managementUDP, TCP, socketsPerformance issues

Application-level Protocol StandardsDomain name servicesApplication standards: SNMP, FTP, TELNET, SMTP,

NNTP, HTTP

Network Security Introduction to CryptographyPublic-key algorithms

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Class Procedures and PoliciesClass attendance and participation (5%)Homework & Labs (15%)Two exams (25% each) and a final (30%)Course Grade is based on straight scale; percentages are on total scores possible:

93 – 100% 4.0

85 – 92 % 3.5

80 – 84 % 3.0

75 – 79 % 2.5

70 – 74 % 2.0

65 – 69 % 1.5

60 – 64 % 1.0

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Class Procedures ……..Class notes and other course materials and resources will be available on the course website:http://www.cse.msu.edu/~cse422/

It is password protected (cse422, tan4me).

Visit this site on regular basis. It is your responsibility!

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Class ProceduresWhen attending the class, we ask you to observe a few simple rules which are meant to create a better learning environment. Come to class on time since we will start lectures right away. Once class begins, we expect students to pay attention and not

read the newspaper or talk, etc. TURN YOUR CELL PHONE OFF. If you have a question, do not hesitate to ask.

Others are likely to have the same question. Do not be afraid to ask questions and slow down the pace of the

class. If we feel there are too many questions and that we must move on, we will say so, but that should not be taken to mean that the question was ``dumb'' or inappropriate.

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Class Procedures …Textbook: Computer Networks, by Andrew Tanenbaum, Fourth Edition.

Students are required to get a copy of this textbook. You will have regular reading assignments from this textbook.

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Class Procedures …Instructor: Dr. Abdol-Hossein Esfahanian

Email: esfahanian@cse.msu.edu

Url: http://www.cse.msu.edu/~esfahani/

Office: 2134EB

Tel: 353-4389

Office Hours: Wed 1:00pm – 2:00pm, or by appointment, or whenever you can find me.

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Class Procedures …Course TA: Bo Wang [wangbo@msu.edu]Office hours will be on Thursdays 10-12 noon.

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Class Procedure …All students will have computer accounts on CSE machines. If your home account is under another domain, then it is your responsibility to have your mail forwarded.

Students are encouraged to work together on homework assignments. However, each student must do his/her write-up.

Unless otherwise specified, exams will be closed-book and will cover material assigned from the texts, notes, handouts, and lectures. For exams only, you are allowed to use an 8½ x 11 note sheet. You should utilize this to write down important formulae, proof techniques etc.

Being caught cheating on ANY aspect of the course is grounds for receiving a grade of 0.0 for the course.

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Academic IntegrityAcademic Integrity is very important in this class and in this university. It is important that students do their work on their own without help from anyone except the instructor or the teaching assistant. Students are permitted to discuss the homework problems with each other. However, the work they turn in must be completely their own. Obviously, no cooperation is permitted during examinations. Students violating this will be dealt with according to the university policy.

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Important datesExam #1Thursday Feb 22, 2007

Exam #2Thursday April 5, 2007

Final:Thursday May 3, 2007, 10:00-12:00 noon

Make note of these dates. Normally there will NOT be any

make-up exams.

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Technologies over the centuries18th Century: Mechanical Systems Accompanying The Industrial Revolution

19th Century: Age of The Steam Engine

20th Century: Information Gathering, Processing, and Distribution. Examples:Worldwide Telephone Network Invention of Radio and TVComputer IndustryLaunching of Communication Satellites

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A brief history of Networking

1961: Kleinrock - queuing theory shows effectiveness of packet-switching1964: Baran - packet-switching in military nets1967: ARPAnet conceived by Advanced Research Projects Agency1969: First ARPAnet node operational

1972: ARPAnet demonstrated

publicly NCP (Network Control

Protocol) first host-host protocol

First e-mail program ARPAnet has 15 nodes

1961-1972: Early packet-switching principles

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Networking History (Cont.)

1970: ALOHAnet satellite network in Hawaii1973: Metcalfe’s PhD thesis proposes Ethernet1974: Cerf and Kahn - architecture for interconnecting networkslate70’s: Proprietary Architectures: DECnet, SNA, XNAlate 70’s: switching fixed length packets (ATM precursor)1979: ARPAnet has 200 nodes

Cerf and Kahn’s internetworking principles: minimalism, autonomy - no

internal changes required to interconnect networks

best effort service model stateless routers decentralized control define

today’s Internet architecture

1972-1980: Internetworking, new and proprietary nets

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Networking History (Cont.)

1983: deployment of TCP/IP1983: smtp e-mail protocol defined 1983: DNS defined for name-to-IP-address translation1985: ftp protocol defined1988: TCP congestion control

new national networks: Csnet, BITnet, NSFnet, Minitel

100,000 hosts connected to confederation of networks

1980-1990: new protocols, a proliferation of networks

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Networking History (Cont.)

Early 1990’s: ARPAnet decommissioned1991: NSF lifts restrictions on commercial use of NSFnet (decommissioned, 1995)early 1990s: WWW hypertext [Bush 1945, Nelson

1960’s] HTML, http: Berners-Lee 1994: Mosaic, later Netscape late 1990’s: commercialization

of the WWW

Late 1990’s:

est. 50 million computers on Internet

est. 100 million+ users

backbone links running at 1 Gbps

1990’s: commercialization, the WWW

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The ARPANET

Growth of the ARPANET (a) December 1969. (b) July 1970.(c) March 1971. (d) April 1972. (e) September 1972.

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Hosts on the Web

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Over the past year, the UK added a net increase of 6.1 subscribers per 100 inhabitants. The US added 4.7 subscribers, while Japan added 2.6. The UK's superior growth rate propelled it past the US and Japan to become second only to Canada among G7 countries surveyed in broadband penetration.

Source: http://www.websiteoptimization.com/bw/0611/

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Total Broadband Subscribers

Over the past year, the US has maintained its lead with 31% of total broadband subscribers worldwide.

Source: http://www.websiteoptimization.com/bw/0611/

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Broadband Penetration by Country and Population Density - June 2006 Source: http://www.websiteoptimization.com/bw/0611/

Lecture 01Tuesday January 09, 2007

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NotableRead Chapter 1

Read the article Nothing but Net

Forthcoming TopicsWhat is a computer networkClassification of networksThe layering concept

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What is a Computer Network?A computer network is an interconnected collection of autonomous computers.Two computer are interconnected if they are able to

exchange informationTwo computer are autonomous if they are capable of

operating independently, that is, neither is capable of forcibly starting, stopping, or controlling the other.

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What is not a Computer Network?Master/slave systems, in which one computer controls several others

single-host networks, consisting of a single computer with an attached collection of terminals.

Multicomputers, such as the old hypercube, which normally operate as a back-end to a host system.

In terms of (operating) systems, there is some confusion between network systems and distributed systems

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Network SystemsAn interconnection of computers through a communication subnet

The user is aware of the networking of different computers

Network services remote login remote file transfer remote job executionmail serviceEtc,

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Distributed SystemsA distributed system is a special case of computer network, in which the network of computers appears as a single system to the user, all operations being performed transparently.

Combination of an interconnection of computers and distributed control programs.

Most operations are transparent to the user.

User sees an integrated service environment; distributed system is hidden from the user.

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Distributed Systems …Provides location-independent services.

The difference lies with the software rather than hardware.

Allows concurrent processing and greater sharing of resources

Permits development of distributed application programs

Ongoing problems in distributed systems load balancing fault-tolerance

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Applications of NetworksAccess to Remote ProgramsSimulationComputer Aided Ed.,Medical Diagnosis

Access to Remote Data BasesReservations For Hotels, AirplanesHome BankingAutomated NewspaperAutomated LibraryAccess to Information System: (e.g. World Wide Web)

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Applications of Networks…Communication MediumElectronic Funds Transfer SystemElectronic MailTeleconferencingWorldwide Newsgroups International Contacts by Humans

Entertainment IndustryVideo On DemandMultiperson real-time simulation gamesSelecting any movie/TV program ever madeLive TV may become interactive with audience

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Social IssuesViews on politics, religion, …., become distributedNewsgroups debate sensitive issuesNetwork operators risk being sued for contentsRights to free speech may be violatedAnonymous messages can be desirable, but ...

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Network Classification based on physical size

Typical Distance

Area covered System Type

10m – 1Km Room, Building Campus Local Area Networks

10 – 100Km City, County, Continent Metropolitan Area, Wide Area Network

Over 100Km Planet Internet

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Network StructureCommunication Subnet (Subnet)Switching Elements (Routers)Transmission Lines (Circuits)

Boundary of the Communication subnet

Routers

Hosts

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Types of Design For SubnetsPoint-to-Point Circuits (Channels)

(a) (b) (c)

(d) (e) (f)

Some possible topologies for a point-to-point subnet(a) Star (b) Loop (c) Tree (d) Complete (e) Intersecting loops (f) Irregular

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Types of Design For Subnets…Broadcast Channels

Communication subnet using broadcasting(a) Bus (b) Satellite or Radio (c) Ring

(a) (b) (c)

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Types of Design For Subnets…Broadcast Subnets May Allocate Channel By:Static Method

TDMA

Dynamic MethodsCentralizedDecentralized

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Classification based on switching techniques

Circuit-switched networksA physical circuit must be established between the two

communicating stations before any exchange of information.

Packet-switched networksNo physical circuit is established in advance.The message is stored and then forwarded at each

intermediate node.