Lect1..ppt - 01/06/05

CDA 6505 Network Architecture

and Client/Server Computing

Lecture 2

Protocols and the TCP/IP Suite

byZornitza Genova Prodanoff

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Outline

•Introduction•Layered Protocol Architecture•Key Features of a Protocol•TCP/IP Layers•TCP and UDP •Operation of TCP and IP•Internetworking Terms •Routers

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Introduction

• Layered protocol architecture• TCP/IP protocol suite• OSI reference model• Internetworking

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The Need for a Protocol Architecture

• Procedures to exchange data between devices can be complex

• High degree of cooperation required between communicating systems

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Example: File transfer

• Requires a data path to exist• Tasks:

– Activate data communication path– Source determines that destination is ready– File transfer app destination file management

app is ready store file for user– File format conversion

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Layered Protocol Architecture

• Modules arranged in a vertical stack• Each layer in stack:

– Performs related functions– Relies on lower layer for more primitive

functions– Provides services to next higher layer– Communicates with corresponding peer layer

of neighboring system using a protocol

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Key Features of a Protocol

• Set of rules or conventions to exchange blocks of formatted data

• Syntax: data format• Semantics: control information (coordination,

error handling)• Timing: speed matching, sequencing

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TCP/IP Layers

• Physical• Network access• Internet• Transport Application

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TCP and UDP

• TCP: – connection-oriented– Reliable packet delivery in sequence

• UDP:– connectionless (datagram)– Unreliable packet delivery– Packets may arrive out of sequence or

duplicated

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Operation of TCP and IP

• IP implemented in end systems and routers, relaying data between hosts

• TCP implemented only in end systems, assuring reliable delivery of blocks of data

• Each host on subnetwork has unique IP address• Each process on each process has unique IP port

number

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TCP Applications

• SMTP: Simple Mail Transfer Protocol• FTP: File Transfer Protocol• telnet: remote login

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Ethernet Example: Network Interface Card

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Ethernet Example: Network Interface Card

RJ-45 connector

AUI connector (Thicknet)

Thinnet connector

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Ethernet LAN Example:Attachment Unit Interface and Media Access Unit

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Ethernet LAN Example: Computers in a Bus Topology

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Ethernet LAN Example: Computers in a Star Topology

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Ethernet LAN Example: Computers in a Ring Topology

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OSI Reference Model

• Application• Presentation• Session• Transport• Network• Data link• Physical

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Internetworking Terms

• Communication network• Internet• Intranet• Subnetwork• End system• Intermediate system• Bridge• Router

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Routers

• Provide link between networks• Accommodate network differences:

– Addressing schemes– Maximum packet sizes– Hardware and software interfaces– Network reliability

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