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CPS 422Computer NetworksMajor Muhammad Faisal Amjad

CS Dept

Internet

Everyone uses it

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We want it Everywhere

Even at our fingertips

We even call and meet each other overthe Internet

Why shouldTV be anexception

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www.UandiStar.org World has become a global village becauseofthe Internet

So What is Internet ??? It is a collection of a very large number ofinter-connected NETWORKS that connectmillions of devices that can communicatewith each other

And why should we study networks

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Introductory (first) course in computer networking Learn principles and Architecture of computer

networking This is NOT a course on network building or specific

usage, However Internet architecture/protocols will be studied to

understand networking principles.

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Goals: learn a lot (not just facts, but principles) enjoy learning Computer Networks (Not as a burden) be able to make intelligent decisions about network

design, use and management be able to pick up and learn details of a particular

system as you need it be able to quickly find protocol descriptions and problem

solutions be able to discuss data communication systems with

supervisors and co-workers on the job (and may beimpress them with high sounding technical jargons)

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Course Information Who is this course for?

o Undergrads of TE and BESE Prerequisites:

o Willingness to work hard (for survival in this course and ultimatelyin your profession)

Course materials:o text: Data and Computer Communications By William StallingsFifth Edition

o text: Data Communications and Networking By BehrouzForouzan, Third Edition

o Other Ref books (if necessary) will be indicated during the course.o WWW readings.o Class notes

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Credit Hours: 3+1 Workload:Coursework amount %ageWritten assignments as needed 10%Announced / unannounced quizzes as needed 10%Midterm Exam 1 30%Final exam 1 50%

Missing quizzes / assignments / exam will land you intotrouble. DONT MISS THEM.

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Networking is a Vast subject and only keyconcepts can be covered in the class.You are expected to read the rest from thebook and other refs.

Feel free to ask questions during theclass about any concepts that are notclear.

Material covered in the class will includesome concepts from other textbooks. Pleasepayattention to the class discussion.

www.UandiStar.orgCourse Outline Networking Overview Layered Approach to Network Architecture Comparison of OSI and TCP/IP architecture Physical Layer (Will not be covered in detailsince Analog & Digital Comm has already beenstudied)

o Analog / Digital Communicationo Transmission Mediao Data Encodingo Interfacingo Multiplexingo Packet Switching / Circuit Switching

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Data Link Layero Error Detection / Correction / Controlo Elementary Data Link Protocolso Sliding Window Protocolso MAC Sub-layer

MAC Protocols (CSMA, ALOHA, WLANs etc.) IEEE 802 Standards for LANs Bridges High Speed LANs

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The Network Layero Internetworking Conceptso Internet Addressingo ARPo IP Connectionless Datagram Deliveryo Routingo IP Error and Control (ICMP)o Subnet and Subnet Extension

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The TransportLayer

o Process to Process Deliveryo User Datagram Protocol (UDP)o Transmission Control Protocol (TCP)o Congestion Controlo Quality of Service (QoS)

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The Application Layero Client-Server Model and the Socket Interfaceo Domain Name System (DNS)o E-mail (SMTP) and File Transfer (FTP)o HTTP and the WWW

NetworkSecurity

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Networking Overview

www.UandiStar.orgData Communication Data Communication is the exchange of data between

two devices via some form of transmission medium Fundamental characteristics of data communication:

o Delivery to correct destinationo Accuracy without errorso Timeliness

Components of data communication:o Messageo Sendero Receivero Mediumo Protocol

Sender

Step 1

MessageTransmission Medium

Receiver

Step 1Protocol Step 2Step 3.

Protocol Step 2Step 3.

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Simplified Communication Model

www.UandiStar.orgSimplified Data Communication Model

www.UandiStar.orgDirection / Timing of Data Flowo Simplex

Direction of DataMonitor

o Half DuplexMainframe

Workstation DataDirection at time 1Workstation

o Full Duplex DataDirection at time 2

WorkstationDataDirection at all times

Workstation

www.UandiStar.orgProtocolA protocol is a set of rules that governsdata communications. It represents anagreement between the communicatingdevices.Without protocol, devices may beconnected but not communicating.

www.UandiStar.orgExample protocolsa human protocol and a computer network protocol:

HiHi

Got thetime?2:00

time

TCP connectionreq.TCP connectionreply.Get http://www.mcs.edu.pk/index.htm

www.UandiStar.orgNetwork Criteria Performance

o e.g. transit time, response timeo Depends upon media, no of users, hardwarecapabilities, software efficiency etc.

Reliabilityo Freq of failureo Failure recoveryo Robustness in a catastrophe

Security

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Mesh Star Bus Ring

Network Topologies

Network Topologies

Mesh Star Bus Ring

www.UandiStar.orgNo of I/O portsrequiredEase ofinstallation /reconfigureLink failureAvailability oflink BW

Mesh Topology

A fully connected mesh network has n(n-1)/2 physical linksto connect n devicesIs the network in figure above a fully connected mesh ?

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Star Topology

HUB / Switch

No of I/O portsrequiredEase ofinstallation /reconfigureLink failureAvailability oflink BW

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Bus TopologyTap Tap Tap Tap

No of I/O portsrequiredEase ofinstallation /reconfigureLink failureAvailability oflink BW

www.UandiStar.orgNo of I/O portsrequiredEase ofinstallation /reconfigureLink failureAvailability oflink BW

Ring Topology

www.UandiStar.orgNetwork Categories Local Area Network (LAN) Metropolitan Area Network (MAN) Wide Area Network (WAN)

Network Categories

LAN MAN WAN(Within a few buildings) (Within a city) (Across many cities) Can you name some other Network Categories ?

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An ExampleNetworkingConfiguration

www.UandiStar.orgInternet Standards An Internet Standard is a thoroughly tested

specification that is useful to and adhered to bythose who work on the Internet.

Any specification begins as an Internet Draft whichis a working document (work-in-progress) with noofficial status and a 6-month lifetime.

Upon recommendation from Internet authorities, aDraft may be published as a Request ForComment (RFC). Each RFC is edited, assigned anumber and made available to all interestedparties.

Visit the URL http://www.ietf.org

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Assignment # 1 (Due: Thur 27thMar2009) Give advantages / disadvantages of variousnetwork topologies studied.

Find out and list other network categories(e.g. LAN/MAN). Give a very brief (2-3lines) explanation of each.

Find out Two Internet Drafts and TwoRFCs from the Internet, Give theirnumbers/names, Topics and their author(s)names.

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