Chapter 2 Protocols and the TCP/IP Suite1

Chapter 2Chapter 2

Protocols and the TCP/IP Suite

Chapter 2 Protocols and the TCP/IP Suite2

Introduction Introduction

Layered protocol architectureTCP/IP protocol suiteOSI reference modelInternetworking

Chapter 2 Protocols and the TCP/IP Suite3

The Need for a Protocol The Need for a Protocol ArchitectureArchitectureProcedures to exchange data between

devices can be complexHigh degree of cooperation required

between communicating systems

Chapter 2 Protocols and the TCP/IP Suite4

Example: File transfer Example: File transfer

Requires a data path to existTasks:

– 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 ArchitectureLayered Protocol Architecture

modules arranged in a vertical stackEach 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 ProtocolKey Features of a Protocol

Set of rules or conventions to exchange blocks of formatted data

Syntax: data formatSemantics: control information

(coordination, error handling)Timing: speed matching, sequencing

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TCP/IP LayersTCP/IP Layers

PhysicalNetwork accessInternetTransport Application

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TCP and UDPTCP and UDP

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

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

duplicated

Chapter 2 Protocols and the TCP/IP Suite9

Figure 2.1Figure 2.1

Chapter 2 Protocols and the TCP/IP Suite10

Figure 2.2Figure 2.2

Chapter 2 Protocols and the TCP/IP Suite11

Operation of TCP and IPOperation 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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Figure 2-3Figure 2-3

Chapter 2 Protocols and the TCP/IP Suite13

Figure 2-4Figure 2-4

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TCP ApplicationsTCP Applications

SMTP: Simple Mail Transfer ProtocolFTP: File Transfer Protocol telnet: remote login

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OSI Reference ModelOSI Reference Model

ApplicationPresentationSessionTransportNetworkData linkphysical

Chapter 2 Protocols and the TCP/IP Suite16

Figure 2.5Figure 2.5

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Internetworking TermsInternetworking Terms

Communication networkInternetIntranetSubnetworkEnd systemIntermediate systemBridgeRouter

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RoutersRouters

Provide link between networksAccommodate network differences:

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

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Figure 2-7Figure 2-7

Chapter 2 Protocols and the TCP/IP Suite20

Figure 2-8Figure 2-8

Chapter 2 Protocols and the TCP/IP Suite21

Figure 2-9Figure 2-9

Chapter 2 Protocols and the TCP/IP Suite22

Figure 2-10Figure 2-10