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Pertemuan 7 Communication Protocols

for E-Business

Matakuliah : M0284/Teknologi & Infrastruktur E-Business

Tahun : 2005

Versi : <<versi/revisi>>

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Learning Objectives

• Explain the idea of a protocol

• Describe the OSI model of communication protocol

• Point out important features of the TCP/IP protocol suite

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Overview

• What is a protocol?

• The Open Systems Interconnection Model

• Understanding the Internet

• The Internet Protocol Suite

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What is a Protocol?

• Rules of communication• Communication consists of small acts• Protocols formalize the notion of acts• Protocols relate to other protocols in terms of

layers

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Protocol Layers

Different functions in a post-office based communication system

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Open Systems Interconnection Model

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OSI Model

Layer 0: The physical media

Layer 1, Physical: Specifications related to transfer of data bits. Modulation techniques, voltages, interfaces

Layer 2, Datalink: Specs related to delivery of frames across two adjacent nodes. Sending and receiving of frames from the media, frame structure, addressing

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The OSI Model

• Layer 3, Network: Specs relating to sending message over the entire network routing, congestion control

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The OSI Model

Layer 4, Transport: Ensure end-to-end delivery function executed at the sender and recipient end

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The OSI Model

• Layer 5, Session: establish, maintain and terminate session

• Layer 6, Presentation: data representation, encryption

• Layer 7, Application: network application, user interface

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The Internet

• Data Centric network• Separation of Communication and data

processing between 2 computers, one called host and the other router

• Packet Switched Network

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The Internet: Packet Switching

Packets travel from sending host to destination host. Along the way the packets are routed from one router to another

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The Internet: Network connecting other networks

A simplified view of the Internet

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The Internet: The Network

• Networks owned by different governments and organizations

• Consists of different levels of backbone national level, regional level

• The backbones are owned and operated by different Internet service providers and governments

• The backbone meet at network access points and metropolitan area exchanges

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Internet Service Provider

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Connecting to an ISP

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Internet Protocol Suite

• Developed independently of OSI

• Can be mapped to OSI model

• Layer 3, network layer: IP, Internet protocol

• Layer 4, transport layer: TCP, transmission control protocol

• Layer 7, application: FTP, HTTP

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The Internet Protocol Suite

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Internet Protocol

• Internet addressing32 bit Internet address:

10000001 00011111 10000001 00011111

is written as 129.31.129.31

• Domain name addressing domain name servers translates an address chaudhury.mis.mgmt.edu to the above IP address

• Different domains: edu, gov, com, mil, net

• New domains: biz, pro, cop, museum, aero, name

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Domain Server Tree

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IP Routing

Routing tables at each router specify for the packet destination address the network address that the packet is to be routed to

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Transmission Control Protocol

• Fulfills the functions of Layer 4, transport layer ensures end-to-end delivery

• Breaks data stream from the application layer into packets (IP datagrams)

• Uses a system of acknowedgement-with- retransmission paradigm