Matakuliah
Tahun
Versi
: M0284/Teknologi & Infrastruktur E-Business
: 2005
: <<versi/revisi>>
Pertemuan 7
Communication Protocols
for E-Business
1
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
2
Overview
• What is a protocol?
• The Open Systems Interconnection
Model
• Understanding the Internet
• The Internet Protocol Suite
3
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
4
Protocol Layers
Different functions in a post-office based communication system
5
Open Systems Interconnection
Model
6
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
7
The OSI Model
• Layer 3, Network: Specs relating to
sending message over the entire network
routing, congestion control
8
The OSI Model
Layer 4, Transport: Ensure end-to-end delivery
function executed at the sender and recipient end
9
The OSI Model
• Layer 5, Session: establish, maintain and
terminate session
• Layer 6, Presentation: data representation,
encryption
• Layer 7, Application: network application,
user interface
10
The Internet
• Data Centric network
• Separation of Communication and data
processing between 2 computers, one called host
and the other router
• Packet Switched Network
11
The Internet: Packet Switching
Packets travel from sending host to destination host. Along
the way the packets are routed from one router to another
12
The Internet: Network connecting
other networks
A simplified view of the Internet
13
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
14
Internet Service Provider
15
Connecting to an ISP
16
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
17
The Internet Protocol Suite
18
Internet Protocol
• Internet addressing
32 bit Internet address:
10000001
00011111
is written as 129.31.129.31
10000001
00011111
• 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
20
IP Routing
Routing tables at each router specify for the packet destination
address the network address that the packet is to be routed to
21
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-withretransmission paradigm
22