NCERT Computer: Chapter 5 – Data Communication and Networking Part 4

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Types of Networks

Network: A network is defined as a group of two or more computer systems linked together. There are several different types of computer networks. Computer networks can be characterized by their size as well as their purpose.

However, from an end user’s point of view there are two basic types:

(1) Local-Area Networks (LANs)

The computers are geographically close together (that is, in the same building).

(2) Wide-Area Networks (WANs)

The computers are farther apart and are connected by telephone lines or radio waves.

Topology

The geometric arrangement of a computer system. Common topologies include bus, star, and ring.

Protocol

The protocol defines a common set of rules and signals that computers on the network use to communicate. One of the most popular protocols for LANs is called Ethernet. Another popular LAN protocol for PCs is the IBM token-ring network.

Architecture

Networks can be broadly classified as using either peer-to-peer or client/ server architecture.

Computers on a network are sometimes called nodes. Computers and devices that allocate resources for a network are called servers.

Local Area Network (LAN)

LAN is a computer network that spans a relatively small area. Most LANs are confined to a single building or group of buildings.

A system of LANs connected in this way is called a wide-area network (WAN).

There are many different types of LANs-token-ring networks, Ethernents, and ARCnets being the most common for PCs.

LANs are capable of transmitting data at very fast rates, much faster than data can be transmitted over a telephone line; but the distance are limited, and there is also a limit on the number of computers that can be attached to a single LAN.

Wide Area Network (WAN)

A WAN is a computer network that spans a relatively large geographical area. Typically, A WAN consists of two or more local-area networks (LANs).

Computers connected to a wide-area network are often connected through public networks, such as the telephone system. They can also be connected through leased lines or satellites. The largest WAN in existence is the Internet.