Introduction toIntroduction to Computer Networks Computer Networks

Aram Mohammad AbdulqadirAram Mohammad AbdulqadirM.C.AM.C.ADepartment of Computer ScienceDepartment of Computer Science

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What is a computer?

•Computer is a machine which consists of various hardware parts and different softwares to process the stored data in memory.

So..

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What is a Computer Network? A network consists of 2 or more computers connected together and they can communicatecommunicate and shareshare resources.

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Why Networking?

1- Sharing information => i.e. data communication

Which one you prefer?

1 OR 2

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2- Sharing hardware or software

3- Centralize administration and support

• E.g. print document

• E.g. Internet-based, so everyone can access the same administrative or support application from their PCs

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Computer Network & Human Society

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How many kinds of Networks?How many kinds of Networks?Aram Mostowfi

How many kinds of Networks?

• Depending on one’s perspective, we can classify networks in different ways:

1. Based on transmission media: • Wired (UTP, coaxial cables, fiber-optic cables) • Wireless

2. Based on network size: • LAN, MAN and WAN

3. Based on management method: • Peer-to-peer and Client/Server

4. Based on topology (connectivity): • Bus, Star, Ring …

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Based on the Transmission Media• Wired Media:

1- Coaxial Cables1- Coaxial Cables 2-UTP Cables 2-UTP Cables 3-Fiber 3-Fiber Optic CablesOptic Cables

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Based on the Transmission Media• Wireless Media:

1- Wi-Fi1- Wi-Fi 2-Bluetooth 2-Bluetooth

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3-Infrared 3-Infrared 4-Microwave4-Microwave

Based on the Transmission Media• Wireless Media: (cont..)

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• Small network, short distance (1m -1000m)• Limited by no. of computers and distance

covered• Examples:

• Network inside the Student Computer Room• Network inside CF502• Network inside your home

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Based on the Network Size• Local Area Network - LAN

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• Metropolitan Area Network-MAN

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Based on the Network Size

• Medium size networks. Distance (1KM - 10KM)

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• A network that uses long-range telecommunication links to connect 2 or more LANs/computers housed in different places far apart.

• Towns, states, countries• More than 10 Kilometers

• Examples:• Network of our Campus• Internet

WANStudent Computer Centre

Your home

USA

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Based on the Network Size• Wide Area Network - WAN

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Based on the Network Size• Wide Area Network – WAN

(cont.)

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• Peer-to-peer network is also called workgroup• No hierarchy among computers all are equal• No administrator responsible for the network

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Based on the Management Method• Peer-to-Peer (P2P) Networks

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Based on the Management Method• Client-Server Network

• Computers are not same.• A computer (Server) administrate the others and its

responsible for all tasks in the network.

Server

Clients

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• How computers are connected together?How computers are connected together?

Bus Topology Ring Topology

Star Topology

Hub

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Based on Topology• Three simple topologies

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Nowadays Computer Networks have spread all over the world not only among computer machines although through many electronically devices to make life easier and use the resources as much as possible.

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ThankiThanking You ng You

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