Computer Network is a set of devices connected through
communication lines. Each device in network is called node. Nodes may be
workstation, server, modem, router, switch etc. which are capable of generating
or receiving data in network. Computer network has following components:-
- Computer system
- Network Integrated Card (NIC)
- Communication lines
- Peripherals
The boarder of any network is called network edge. Network edge
generally consists of host or any other peripherals. Host is computer that may
be client, server or peer.
The main purpose of network is sharing resources that may be
either hardware or software. This creates the environment for sharing, transferring
information in network.
A computer network must have the following properties:
ü Reliable:
It means to resist with failure. If some
link is down then there must be alternative link for communication.
ü Secure:
Network share valuable information that may
be confidential. Thus network must be secure from outer attack. Security can be
maintained through firewall, access list or other means.
ü Timeliness:
Network must be capable of transferring information
in time.
A simple
Computer Network:
Types of
network:
1. Local Area Network (LAN):
It is network owned by one organization, generally located in small
geographical area. It generally has high data transfer rate and more secure.
For example: Intranet.
2. Wide Area Network (WAN):
It is network owned by different organization spread in large
geographical area. It consists of heterogeneous networks that may be wired or
wireless. Generally data transfer rate is lower than LAN and some security
technique must be employed. For example: Internet.
3. Metropolitan Area Network (MAN):
MAN
spreads larger area than LAN and is owned by one company.
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