What is a Network

NETWORKS

What is a network?

Collection of computers and devices connected via communications devices and transmission media Networks can be classified by the geographical area they cover

NETWORKS

What is a network

There are 3 types of computer networks

LAN (Local Area Networks)

MAN (Metropolitan Area Network)

WAN(Wide Area Network)

Local area network (LAN)

Network in the limited geographical areas such as home or office building

LAN covers a small region of space typically a single building, schools, or at home

Local area network (LAN)

Local area network (LAN)

Local area network (LAN)

LAN can pass data to one and all as well as can

      share resources.

Once PC’s are physically connected, software

designed specifically for LAN allows the exchange of

program and data files among users connected to the

network.

The network software allows any user to access

shared data storage(hardware) and output devices

(printers) connected to networks.

Local area network (LAN)

A group of computers and other devices dispersed over a relatively limited area say within a building and connected by a communication link that enables each device to interact with any other device on the network is called LAN.

Advantages of LAN

LAN allows sharing of expensive resources such as laser printers and high-capacity, high-speed mass storage devices among a number of users.

LAN allows the high-speed exchange of essential information between key people in an organization. If properly managed, this will provide greater efficiency and productivity.

Advantages of LAN

Through LAN, one can store all critical data at a central place and many users can then access and work on this data. LAN allows the high-speed exchange of essential information between key people in an organization. If properly managed, this will provide greater efficiency and productivity.

Since data can be stored centrally, you can take the back-up of all important files daily on tapes or hard disk drives,

Disadvantages of LAN

LAN software requires memory space in each of the computers used on the network. About 20% of the computer’s memory will be needed to manage the network interface. This reduces the memory space available for user programs.

LAN adds another level of complexity to the

computer operation. Users may have difficulty in learning the network commands.

Disadvantages of LAN

Some control on the part of a user is lost. For example, suppose you have to share a printer with other users, then you can face a situation where the entire network suddenly locking up because one user has made a mistake.

LAN has security problems. Some types of the security systems must be implemented for protecting data. Any user can play foul and destroy the centrally stored data easily on a network.

Example on LAN:

Two or more computers connected in a

     the building or small office or an internet café.

Metropolitan area network(MAN)

MAN is a data network intended to serve an area approximately that of a large city.

Such networks are being implemented by techniques like running fiber cables through subway tunnels and satellites.

A popular example of MAN is 

SDBS(Switched Multimegabit Data Service).

Example of MAN:

A popular example of MAN is 

SDBS(Switched Multimegabit Data Service).

SDBS is a high-speed, packet-switched,

datagram-based WAN networking

the technology used for communication over

public data networks(PDNs). SMDS can use

fiber- or copper-based media; it supports

speeds of 1.544 Mbps.

Wide Area Network (WAN)

A network that covers a large geographic area using many types of media

Internet is the world’s largest WAN

Can be a collection of LANs or WANs or the mix of two with a very large geographical area for an instant a country or even beyond the border

Dedicated transoceanic cabling or satellite uplinks may be used to connect this type of network.