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CHAPTER 1INTRODUCTION TO

NETWORKINGBasic Concepts of Computer NetworksImproved by W.N.Wahidah

Dec20131

Department of Information and

Communication Technology

DIPLOMA IN INFORMATION

TECHNOLOGY

(NETWORKING)

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NETWORK

2

Set of devices (nodes) connected bycommunication links.

Node can be a computer, printer or any otherdevice capable of sending and/or receiving data

generated by other nodes on the network.

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(1)

3

Hardware & Software sharing

An important advantage of networking is the ability to share

hardware. For an example, a printer can be shared among theusers in a network so that theres no need to have individual

printers for each and every computer in the company. This will

significantly reduce the cost of purchasing hardware.

The software sharing allows the users to download softwarefrom internet. Facilitate Collaboration

Collaboration means that users in different

locations can work together on documents

and speak together while they work.

Example Google Drive, multiple people can

view and edit a Google Docs file

simultaneously. More importantly, they don't

have to worry about creating duplicate

copies of the same file. With Google Docs,

everyone working on a project makes

changes to the same master document.

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Facilitate in collaboration with data and

information sharing.

Institutions are continually striving to enhance the

process of dissemination of knowledge. The e-

learning platform deliver learning materials include

interactive activities, assessments, and

feedback.Online courses can contain voice, data,

and video and are available to the students at any

time from any place. (Example: CIDOS)

Give many benefits to businesses in term of

current and accurate training materials, cost

reduction and availability of training to wide

audience. Online training is not dependent on

travel schedule, instructor availability, or physical

class size.

ADVANTAGES OF NETWORKING (2)

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(1)

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Effective communication

New development has improved and

enhanced human communication fromface-to-face to the used of media.

Current networks have evolved to carryvoice, video streams, text and graphicsbetween many different types of devicesthat enable people to interact directly witheach other almost instantaneously.(Examples: Facebook, Twitter, Wechat,Whatsapp, Instant Messaging(IM),Podcasting)

Internet usage has improved peoplelives.

Internet connected people with the wholeworld. Tourists anywhere will able toaccess a site of a city and see images of

a town. Children are interested inlearning to read and write.

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Data security and management The technology of Intranet and

client-server network helps toenhance the security of the dataresides in the server. The used offirewall protects the resources of aprivate network from users fromother networks.

Companies provide suppliers,vendors, and customers limitedaccess to corporate data to checkorder status, inventory and others.

Performance enhancement andbalancing Remote AccessBusiness

applications can be accessedremotely as if employees were onsite using the network.

Workers in any location can reacheach other and access resources

on the network.

ADVANTAGES OF NETWORKING (1)

Firewall

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ADVANTAGES OF

NETWORKING (2)

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The set-up

of networkscan be in

many forms.

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COMPONENTS

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Messageinformation/data to be communicated. Consist of text,

numbers, pictures, sound or video. Senderdevice that sends the data message. Can be computer,

workstation, telephone, video etc.

Receiverdevice that receives the message. Can be computer,workstation, telephone, video etc.

Mediumphysical path which a message travels from sender to

receiver, wired or wireless. Example of wired medium include : twisted-pair wire, coaxial cable, fiber optic cable, and wireless medium such asradio waves.

Protocolset of rules that governs data communication. Representagreement between communicating devices.

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NETWORK COMPONENTS (1)

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Can be grouped into four main categories:1. Hosts

2. Shared peripherals

3. Networking devices

4. Networking media

Hosts

Devices that send and receive messages directlyacross the network.

Eg: personal computers and network attached

printers.

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NETWORK COMPONENTS (2)

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Shared peripheralsNot directly connected to the network, but instead are

connected to hosts.

The host is then responsible for sharing the peripheral across

the network.

Hosts have computer software configured to enable people on

the network to use the attached peripheral devices.

Eg: cameras, scanners, locally attached printers

Networking devicesConnect other devices, mainly hosts.

Move and control network traffic.

Eg: hubs, swithes, routers (devices)

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NETWORK COMPONENTS (3)

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Networking media

Provides connections between hosts and network devices. Example: WIRELESS

TECHNOLOGY

COPPER FIBRE OPTIC

Wireless Router

or Access Point

Broadband dongle

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NETWORK COMPONENTS (4)

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Network Interface Card

Repeater

Hub

Bridge Switch

Router

Wireless access pointswitch

bridge

router

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NETWORK COMPONENTS -

ACTIVITY

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Identifythe network components:

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CLIENT-SERVER NETWORK

14

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HostoAll computers connected to a network that participate

directly in network communication

o Can send and receive messages on the network

o Can act as a client, a server or both. The software installed

on the computer determines which role the computer plays. Server

o Host that have software installed that enable them toprovide information, like email or web pages, to other hostson the network.

o Each service requires separate server software.

Cliento computer hosts that have software installed that enable them to

request and display the information obtained from the server. Anexample of client software is a web browser, like Internet Explorer.

CLIENT-SERVER NETWORK

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CLIENT-SERVER NETWORK

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PEER-TO-PEER NETWORK (1)

17

Client and server software usually runs onseparate computers, but it is also possible for one

computer to carry out both roles at the same time.

In small businesses and homes, many computers

function as the servers and clients on the

network.

Consists of two directly connected computers

using a wired or wireless connection.

Multiple PCs can also be connected to create a

larger peer-to-peer network but this requires a

network device, such as a hub, to interconnect

the computers.

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PEER-TO-PEER NETWORK (2)

18

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PEER-TO-PEER NETWORK -

ACTIVITY

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Identify if the computer is acting as a server, a client,or both for each scenario. Diana connects to the Internet and downloads a file

from a site using a protocol called File TransferProtocol. Is Dianas computer acting as a server, a

client, or both? Syafiq connects into an e-learning web site to learn

about networking. Is Syafiqscomputer acting as aserver, a client, or both?

Alin has a dedicated computer used for sharing her

files. Adnan is downloading a folder fromAlinscomputer. IsAlinscomputer acting as a server, aclient, or both?

Farid has a video game loaded on his computer. Ain

has the same video game loaded on her computer.They are playing each other over the network. IsAins

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NETWORKS

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Local Area Network (LAN)

Metropolitan Area Network (MAN) Wide Area Network (WAN)

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LOCAL AREA NETWORK (LAN)

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LAN has the following characteristics:

Coverage area is generally a few kilometers (up to 10 km and typically around 1km)

Using different dedicated transmission medium you can achieve the transmission rate of 1 Mb/s to 100

Mbit / sec or higher, with the further development of LAN technology is currently being developed

toward higher speed (e.g. 155Mbps, 655Mbps and 1000Mbps etc.).

In LAN you can run the multiple devices to share a transmission medium.

You can use the different topology mainly bus and ring in LAN.

The communication quality is better IN LAN, the transmission error rate are low as compare to WAN.

LAN support a variety of communications transmission mediumsuch as a cable (thin cable, thick cable,

and twisted pair), fiber and wireless transmission.

A LAN usually has low cost, installation, expansion and maintenance and LAN installation is relatively

simple, good scalability.

http://www.w7cloud.com/what-is-wan-and-its-features/http://www.w7cloud.com/what-is-wan-and-its-features/

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(MAN)

1. The network size falls intermediate between LANs and WANs. A MAN typically

covers an area of between 5 and 50 km diameter. Many MANs cover an area the

size of a city, although in some cases MANs may be as small as a group of

buildings or as large as the North of Scotland.

2. A MAN (like a WAN) is not generally owned by a single organisation. The MAN,

its communications links and equipment are generally owned by either a

consortium of users or by a single network provider who sells the service to the

users. This level of service provided to each user must therefore be negotiated

with the MAN operator, and some performance guarantees are normally

specified.

3. A MAN often acts as a high speed network to allow sharing of regional resources

(similar to a large LAN). It is also frequently used to provide a shared connectionto other networks usin a link to a WAN.

22

A metropolitan area network is a computer network that

usually covers a city. A metropolitan area network is known to

connect local area networks to provide internet access to a

large area.

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WIDE AREA NETWORK (WAN)

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WANspans a large geographic area, such as a state, province or country.

WANs often connect multiple smaller networks, such as local area networks (LANs) or

metro area networks (MANs).The world's most popular WAN is the Internet.

Telecommunications Service Providers manage large area networks that can span long

distances. TSPs transported voice and data communications on separate networks.

These networks that connect LANs in geographically separated locations are referred

to as Wide Area Networks (WANs).

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TOPOLOGIES

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Created to record where each

host is located and how it is

connected to the network.

Shows where the wiring is

installed and the locations of the

networking devices that connectthe hosts.

Icons are used to represent the

actual physical devices within the

topology map. It is very important to maintain

and update physical topology

maps to aid future installation

and troubleshooting efforts.

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TOPOLOGIES

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Map groups hosts by how they use the network, no

matter where they are physically located.

Host names, addresses, group information and

applications can be recorded.

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NETWORK TOPOLOGY TYPES

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Ring

Star

Mesh

Fully

Connected

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TOPOLOGIES

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Bus

Ends of bus are not connected. Terminatoreliminate signal feedback /signal loss.

Common speeds are 10, 100 and 1000Mbps.

Mediatwisted-pair wires/fiber optic cables

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NETWORK TOPOLOGIES (4)

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Star Consists of a wiring hub to which nodes or other

hubs are directly connected.

Hub used to form the connection between network

nodes.

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NETWORK TOPOLOGIES (5)

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Ring The medium forms a closed loop and all stations

are connected to the loop or ring.

Data is transmitted from node to node in one

direction.

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NETWORK TOPOLOGIES (6)

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Mesh Each node connected to all other nodes (or most

other nodes).

Redundancy provides reliability.

Hybrid

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NETWORK

TOPOLOGIES

Different characteristics? Search for the answers.

Look also for the advantages and disadvantages

of each topology.

31

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ORGANIZATIONS THAT SET

STANDARDS FOR NETWORKING

a. American National Standards Institute (ANSI)b. Electronic Industries Alliance (EIA) and

Telecommunications Industry Association (TIA)

c. Institute of Electrical and Electronic Engineers(IEEE)

d. International Organization for Standardization

(ISO)

e. International Telecommunication Union (ITU)f. Internet Society (ISOC)

g. Internet Assigned Numbers Authority (IANA) and

Internet Corporation for Assigned Names and

Numbers (ICANN)32

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To be continue..