pengantar dmj

7/29/2019 Pengantar DMJ

1/52


2/52

Uses of Computer Networks

us ness pp ca ons

Home Applications

Mobile Users

Social Issues


3/52

Business Applications of Networks

A network with two clients and one server.


4/52

Business Applications of Networks (2)

The client-server model involves requests and replies.


5/52

A Communications Model

Source

Transmitter

Transmission System

Receiver

Destination

Takes incomin data


6/52

Simplified Communications Model -


7/52

Key Communications Tasks Transmission System Utilization

Interfacing

Signal Generation Synchronization

Exchange Management

Error detection and correction

Recovery

Messa e formattin

Security

Network Management


8/52

Simplified Data Communications


9/52

Networking

Point to point communication not usually practical

Large set of devices would need impractical

Solution is a communications network


10/52

Home Network Applications

ccess to remote n ormat on

Person-to-person communication

Interactive entertainment


11/52

Home Network Applications (2)

In peer-to-peer system there are no fixed clients and servers.


12/52

Home Network Applications (3)

Some forms of e-commerce.


13/52

Network Hardware

Metropolitan Area Networks

Wide Area Networks

Wireless Networks

Home Networks


14/52

Broadcast Networks

Types of transmission technology

roa cas n s

Point-to- oint links


15/52

Broadcast Networks (2)

Classification of interconnected processors by scale.


16/52

Local Area Networks

Two broadcast networks

(b) Ring


17/52

Metropolitan Area Networks

A metropolitan area network based on cable TV.


18/52

Wide Area Networks

Relation between hosts on LANs and the subnet.


19/52

Wide Area Networks (2)

A stream of packets from sender to receiver.


20/52

Wireless Networks

Categor es o w re ess networ s: S stem interconnection

Wireless LANs

Wireless WANs


21/52

Wireless Networks (2)

(a) Bluetooth configuration

(b) Wireless LAN


22/52

Protocols Used for communications between entities in a system

Must speak the same language

Entities User applications

e-mail facilities

terminals Systems

Computer

Terminal

Remote sensor


23/52

Key Elements of a Protocol

Syntax

Data formats Si nal levels

Semantics

Error handling

m ng Speed matching

Sequencing


24/52

Protocol Architecture

Task of communication broken up into modules

For example file transfer could use three modules

File transfer application

Network access module


25/52

Network Software

Layers, protocols, and interfaces.


26/52

Protocol Hierarchies (2)

I likerabbits

Location A

3 3

Location B

Message PhilosopherJ'aimebien leslapins

TranslatorInformationfor the remoteL: Dutch L: Dutch

2 2

translatorIk vind

konijnen

leuk

Ik vind

konijnen

leuk

1 1

Secretary

Informationfor the remotesecretary

Fax #---

L: Dutch

Ik vind

konijnen

Fax #---

L: Dutch

Ik vind

konijnen

The philosopher-translator-secretary architecture.


27/52

Protocol Hierarchies (3)

Example information flow supporting virtual communication in layer 5.


28/52

Design Issues for the Layers

Addressing

Error Control

Flow Control

Multiplexing Routing


29/52

Connection-Oriented and Connectionless

erv ces

Six different types of service.


30/52

Reference Models

The TCP/IP Reference Model

A Comparison of OSI and TCP/IP

A Critique of the OSI Model and Protocols A Critique of the TCP/IP Reference Model


31/52

Reference Models (2)

The TCP/IP reference model.


32/52

Reference Models (3)

Protocols and networks in the TCP/IP model initially.


33/52

Architecture of the Internet

Overview of the Internet.


34/52

Ethernet

Architecture of the original Ethernet.


35/52

Wireless LANs

(a) Wireless networking with a base station.

(b) Ad hoc networking.


36/52

Wireless LANs (2)

The range of a single radio may not cover the entire system.


37/52

Wireless LANs (3)

A multicell 802.11 network.


38/52

Network Standardization

o s o n e e ecommun ca ons or

Whos Who in the International Standards World

o s o n t e nternet tan ar s or


39/52

Wide Area Networks

Large geographical area

Crossin ublic ri hts of wa

Rely in part on common carrier circuits Alternative technologies

Circuit switching

Packet switching Frame relay

As nchronous Transfer Mode (ATM)


40/52

Circuit Switching

Dedicated communications path established for the

e.g. telephone network


41/52

Packet Switching

Data sent out of sequence

Packets passed from node to node between source anddestination

Used for terminal to computer and computer to computer

communications


42/52

Frame Relay

Packet switching systems have large overheads to

Modern systems are more reliable

Most overhead for error control is stripped out


43/52

Asynchronous Transfer Mode

Evolution of frame relay

e over ea or error con ro

Fixed packet (called cell) length Anything from 10Mbps to Gbps

technique


44/52

Simplified File Transfer Architecture


45/52

Protocols in Simplified Architecture

TCP/IP P l A hi


46/52

TCP/IP Protocol Architecture

Developed by the US Defense Advanced Research Project Agenc

or s pac e sw c e ne wor

Used by the global Internet

.

Application layer

Internet layer

Physical layer

TCP/IP P l A hi M d l


47/52

TCP/IP Protocol Architecture Model

OSI M d l


48/52

OSI Model

Open Systems Interconnection

Organization for Standardization (ISO)

A theoretical system delivered too late!

TCP/IP is the de facto standard

OSI TCP/IP


49/52

OSI v TCP/IP

St d d


50/52

Standards

Required to allow for interoperability between equipment

Advantages

Ensures a large market for equipment and

software

Allows products from different vendors to

commun cate

Disadvantages

reeze ec no ogy

May be multiple standards for the same thing

St d d O i ti


51/52

Standards Organizations

ISO - orma y

ATM forum

REFERENCES


52/52

REFERENCES

. , ,

Hall, 2007. William Stallin s, Data And Com uter Communications

7th Edition, Prentice Hall, 2007.

pengantar dmj

Documents