Introduction to Networking

A network consists of 2 or more computers

connected together, and they can communicate

and share resources (e.g. information)

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Why Networking?

• Sharing information — i.e. data communication

• Do you prefer these?

• Or this?

Creating Computer

Network

Network Benefits

1.Ease Of Access

2.Work From Home

3.Share Resources

4.Share Information

5.Increase Productivity

6.Share Programs

7.Administration

8.Security

Transmission MediaTwo main categories:

Guided ― wires, cables

Unguided ― wireless transmission, e.g. radio, microwave, infrared, sound, sonarTwisted-Pair cables: Unshielded Twisted-Pair (UTP) cablesShielded Twisted-Pair (STP) cables

Coaxial cablesFiber-optic cables

Types Of NetworksTwo types of networks are LAN and WAN:

#. LAN (Local Area Network) – A group of devices

sharing resources in a single area such as a room or a

building.

#. MAN (Metropolitan Area Network) – Collection

of local area network sharing information in

geographical area such as a city or town.

#. WAN (Wide Area Network) – Two or more LANs

communicating, often across large distances. The

most famous WAN is the Internet.

• Local Area Network (LAN)• Small network, short distance

•A room, a floor, a building

•Limited by no. of computers and distance covered

•Usually one kind of technology throughout the LAN

•Serve a department within an organization

• Examples:

•Network inside the Student Computer Room

•Network inside CF502

•Network inside your home

• Metropolitan Area Network (MAN)

• It is a collection of local area network.

• Geographical Area :- City, Town

Example

• Branches of local bank of city

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• Wide Area Network (WAN)

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

• Towns, states, countries

• Examples:

• Network of our Campus

• Internet

WAN

Student Computer Centre

Your home

USA

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Topology ― 3 basic types

• How so many computers are connected together?

Bus Topology Ring Topology

Star Topology

Hub

• Bus Topology•Simple and low-cost•A single cable called a trunk (backbone, segment)•Only one computer can send messages at a time•Passive topology - computer only listen for, not

regenerate data

• Star Topology•Each computer has a cable connected to a single point

•More cabling, hence higher cost

•All signals transmission through the hub; if down, entire network down

•Depending on the intelligence of hub, two or more computers may send message at the same time

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How to construct a network with Bus / Star Topology?

Star Topology

Bus Topology

BNC T-Connector

• Ring Topology• Every computer serves as

a repeater to boost signals

• Typical way to send data:

•Token passing

•only the computer who

gets the token can send

data

• Disadvantages

•Difficult to add computers

•More expensive

• If one computer fails, whole network fails

Network Protocol – Specifications that define the network data

communication procedures to follow when sending and receiving

data.

1. TCP/IP (Transport Control Protocol / Internet Protocol) –

the most common network protocol used by most companies

and home users as a standard protocol. Used to access the

Internet.

2. IPX/SPX (Internetwork Packet Exchange/Sequenced

Packet Exchange) – original protocol used for connecting to

Novell networks. Now TCP/IP is the standard protocol used.

3. NetBEUI (NetBIOS Enhanced User Interface) – is a non-

routable protocol used in simple networks; commonly found

on peer-to-peer networks.

4. HTTP (Hypertext transfer protocol) – It is a set of rules for

transferring files (text, graphic images, sound, video, and

other multimedia files) on the World Wide Web.

The

End