EE-353 Computer NetworksEE-353 Computer Networks

Dr. Zawar Hussain ShahDr. Zawar Hussain Shah

Assistant ProfessorAssistant Professor

HoD Telecommunications and NetworksHoD Telecommunications and Networks

Department of Electrical EngineeringDepartment of Electrical Engineering

SEECS, NUSTSEECS, NUST

Introductory LectureIntroductory Lecture

Today’s LectureToday’s Lecture

What is a Computer Network?What is a Computer Network? Applications of Computer NetworksApplications of Computer Networks Why Study Computer Networks?Why Study Computer Networks? Grading PolicyGrading Policy Course ObjectivesCourse Objectives Course ContentsCourse Contents BooksBooks PoliciesPolicies Contact DetailsContact Details

What is a Computer What is a Computer Network?Network?

A Computer Network is an interconnected group of autonomous computing nodes which can meaningfully and (preferably) controllably communicate with one-another.

Rules and conventions that allow meaningful and unambiguous communication between members of a Computer Network are collectively called Network Protocols.

In real-life networks, often a set of related functions are handled by a group of closely tied protocols which constitute a Protocol Family (also known as a Protocol Suite).

Applications of Computer Applications of Computer NetworksNetworks

Why Study Computer Networks?Why Study Computer Networks?

Increased productivity through efficient Increased productivity through efficient usage of networking technology.usage of networking technology.

Skills to develop state of the art Skills to develop state of the art innovations.innovations.

Improved employment and earning Improved employment and earning potential.potential.

MS, PhDs and other short courses (CCNA MS, PhDs and other short courses (CCNA etc).etc).

Course ObjectivesCourse Objectives

Objectives of this course are,• Conceptual introduction to Computer Networks

and its design principles.• Understand the TCP/IP protocol suite. • Form a basic understanding of the principles

upon which the global Internet was designed. • Understanding network protocols in detail.• Core principles that have shaped popular

networking protocols.

Course ContentsCourse Contents

LabsLabs

Wireshark (packet analyzer)Wireshark (packet analyzer) Graphic Network Simulator (GNS3)Graphic Network Simulator (GNS3) Socket ProgrammingSocket Programming

Text BookText Book

Reference BooksReference Books

Grading PolicyGrading Policy

•Theory 75%

•Labs 25%

Grading PolicyGrading Policy

Quizzes 10 % OHT-1&OHT-2 30 %

Assignments 05 %Final Exam 45 % Project 10%

PoliciesPolicies Bring your own calculator, pen paper etc..Bring your own calculator, pen paper etc.. You will not be allowed to borrow anything You will not be allowed to borrow anything

from anyone during any quiz/test.from anyone during any quiz/test. No late work will be accepted (unless No late work will be accepted (unless

arrangements have been made in advance).arrangements have been made in advance). Ask questions; participate actively in class.Ask questions; participate actively in class. You are allowed to talk to the instructor only.You are allowed to talk to the instructor only.

PoliciesPolicies

You are responsible for what is covered in You are responsible for what is covered in class – even if you don’t attend the class.class – even if you don’t attend the class.

Deficiency in attendance may lead to Deficiency in attendance may lead to termination or relegation. termination or relegation.

You are encouraged to help each other with You are encouraged to help each other with your homework assignments – but you must your homework assignments – but you must submit your own work.submit your own work.

If you are found to be cheating, you will fail If you are found to be cheating, you will fail the assignment/quiz.the assignment/quiz.

PoliciesPolicies

If you have any learning disabilities or special If you have any learning disabilities or special needs, please let me know in advance through needs, please let me know in advance through email or personal meeting.email or personal meeting.

Quizzes are mostly unannounced, however, Quizzes are mostly unannounced, however, announced quizzes can also be taken.announced quizzes can also be taken.

Course material on LMS.Course material on LMS.

Contact DetailsContact Details

Office: Office: Faculty Block, Ground Floor, A-Faculty Block, Ground Floor, A-

125125Phone No: 051-90852129Phone No: 051-90852129

Consulting Hours: Consulting Hours: Friday 12 pm– 1pmFriday 12 pm– 1pm

Email:Email:zawar.hussain@seecs.edu.pkzawar.hussain@seecs.edu.pk

Exceptional meeting:Exceptional meeting:Send me an email and get time.Send me an email and get time.

Chapter 1:Introduction Computer

Networking: A Top Down Approach ,

4th edition. Jim Kurose, Keith

Ross

Computer Networks

Chapter 1: IntroductionOur goal: get “feel” and

terminology more depth, detail

later in course approach:

use Internet as example

Overview: what’s the Internet? what’s a protocol? network edge; hosts, access

net, physical media network core: packet/circuit

switching, Internet structure performance: loss, delay,

throughput Protocol layers, service

models History of Internet

What’s the Internet: “nuts and bolts” view

Interconnects millions of computing devices: hosts = end systems running network

apps Home network

Institutional network

Mobile network

Global ISP

Regional ISP

router

PC

server

wirelesslaptop

cellular handheld

wiredlinks

access points

communication links fiber, copper, radio,

satellite transmission rate =

bandwidth (bits/sec) routers: forward

packets (chunks of data)

What’s the Internet: “nuts and bolts” view protocols control sending,

receiving of msgs e.g., TCP, IP, HTTP, Skype

Internet: “network of networks” public Internet versus

private intranet

Internet standards IETF: Internet Engineering

Task Force RFC: Request For Comments

IETF standard DocumentsMore than 5000 RFCs

Home network

Institutional network

Mobile network

Global ISP

Regional ISP

What’s the Internet: A Service View

Communication infrastructure that provides services to applications: Involve multiple end system

that exchange data with each other.

Web, VoIP, email, games, e-commerce, file sharing

Applications do not run on the routers

Communication services provided to applications: reliable data delivery from

source to destination (connection oriented)

“best effort” (unreliable) data delivery (connection less)

What’s a protocol?Human Protocols: “what’s the time?” “I have a question” Interview

… specific msgs sent… specific actions

taken when msgs received, or other events

Network Protocols: machines rather than

humans all communication

activity in Internet governed by protocols

protocols define format, order of msgs sent and

received among network entities, and actions taken on msg transmission, receipt

What’s a protocol?a human protocol and a computer network protocol:

Hi

Hi

Got thetime?

2:00

TCP connection request

TCP connectionresponseGet http://www.awl.com/kurose-ross

<file>time

The Network Edge: end systems (hosts):

run application programs e.g. Web, email at “edge of network”

client/server

peer-peer

client/server model client host requests,

receives service from always-on server

e.g. Web browser/server; email client/server Peer-Peer model:

minimal (or no) use of dedicated servers

e.g. Skype, BitTorrent, Kazaa

More in Chapter 2