28665722 Computer Networks Ppt

7/29/2019 28665722 Computer Networks Ppt

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WELCOMEA POWER POINT PRESENTATION ON

Co-elucidated by

KUMAR ABHISHEK (C.Sc.E)&

KUMAR MURLIDHAR (E.C.E)


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A Computer Network is an interconnection of a

group of computers. Networks may be Classifiedby what is called the network layer at which they

operate according to basic reference models

considered as standards in the industry such as

the four-layer Internet Protocol Suite model.


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On the basis of SCALE


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A network covering a small geographic area, like a home,office, or building.

Current LANs are most likely to be based on Ethernettechnology.


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Between LANs and WANs

Traditional point-to-pointand switched networks in

WANs inadequate forgrowing needs of

organizations

e.g. Wireless networks, metropolitanextensions to Ethernet

Requirement for highcapacity private and publicnetworks at low costs over

a large area


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A WAN is a data communications network that covers a relatively

broad geographic area (i.e. one city to another and one country toanother country) and that often uses transmission facilities provided

by common carriers, such as telephone companies.


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Intranet

Extranet

Theinternet

An INTRANET is a set ofinterconnected networks, using

the Internet Protocol and uses Ip-

base tools such as web browsers,that is under the control of asingle administrative entity.

An EXTRANET is a network or

internetwork that is limited inscope to a single organization orentity but which also has limited

connections to the networks


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Evolved from ARPANET, 1969Advanced Research ProjectsAgency (ARPA),U.S. Departmentof Defense.

Began in four locations: UCLA,University of Santa Barbara, theUniversity of Utah, and SRI(Stanford Research Institute)

WWW was developed inSpring 1989, at CERN (the

European Laboratory for ParticlePhysics) by Tim Berners-Lee.

Explosive growth came with firstgraphically oriented browser,Mosaic, 1993


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1. BUS TOPLOGY

Each node is daisy-chained

(connected one right afterthe other) along the same

backbone. Information

sent from a node travels

along the backbone until it

reaches its destinationnode.


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Similar to a bus network,

rings have nodes daisychained, but the end of the

network in a ring topology

comes back around to the

first node, creating a

complete circuit. Eachnode takes a turn sending

and receiving information

through the use of a token.


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In a star network, eachnode is connected to a

central device called a hub.

The hub takes a signal that

comes from any node and

passes it along to all theother nodes in the

network.


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CONDUCTIVE: twisted pairs and coaxialcables

ELECTROMAGNETIC: microwave

LIGHT: lasers and optical fibers (need

clear line of sight)

WIRELESS inner/ outer space ; satellite(omnidirectional security issues)


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File Transfer, Email, Remote Login

ASCII Text, Sound (syntax layer)

Establish/manage connection

End-to-end control & error checking

(ensure complete data transfer): TCP

Routing and Logical Addressing: IP

Two party communication: Ethernet

How to transmit signal; coding

Hardware means of sending and receiving data on a carrier

THE OSI REFERENCE MODEL


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This protocol, the core of the World Wide Web,facilitates retrieval and transfer of hypertext(mixed media) documents. Stands for the

HypertextT

ransfer protocol

HTTP

A remote terminal emulation protocol thatenables clients to log on to remote hosts on thenetwork.Telnet

Used to remotely manage network devices.Stands for the Simple Network ManagementProtocol.

SNMP


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Confidentiality Integrity

Availability

Authenticity

SecurityRequirements


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Eavesdroppingon

transmissions Release of

messagecontents

Difficult todetect

Can beprevented

PassiveAttacks

Masquerade Replay

Modification ofmessages

Denial of service

Easy to detect

Hard to prevent

ActiveAttacks


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Ingredients

a) Plain text

b) Encryption algorithmc) Secret key

d) Ciphertext

e) Decryption algorithm


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THE RSA ALGORITHM Key Generation

Selectp, q p and qboth prime,p { q

Calculate n =p q

Calculate J(n)=(p 1)(q 1)

Select integer gcd (J(n), e)=1;

1 < e < J(n)

Calculate d de mod J(n)=1

Public key KU = {e, n}

Private key KR = {d, n}

Encryption

Plaintext: M< n

Cipher text: C=Me (mod n)

Decryption

Cipher text: C

P

laintext:M=

Cd (

modn)


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Elements ofNetwork

Management

Fault

Accounting

Performance

Security


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1.THE INTERNET GRID 2.THE GOOGLE WAVES

Grid computing is the combination ofcomputer resources from multipleadministrative domains applied to acommon task, usually to a scientific,

technical or business problem thatrequires a great number of computerprocessing cycles or the need to process

large amounts of data.

Google Wave is It is a web-based

service, computing platform, and

communications protocol designed

to merge e-mail, instant messaging,wikis, and social networking.


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Computer Networks By Andrew Tenenbaum.

Digital Communication And Networking by Behrouz A. Forouzan.

Communication Networks by Alberto Leon Garcia & IndraWidjaja.

www.google.com, www.dogpile.com, www.ask.com,

www.compnetworking.about.com

28665722 Computer Networks Ppt

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