Network Introduction

Networking Introduction

A computer network is interconnection of a group computer that can communicate and other devices, such as printers, are connected by cables and other communication media. The data is shared between the computers. A network, in addition to facilitating data communication, allows resources to be shared among all the systems connected to the network.

Advantages of Networking
Following are the advantages of network:
1. Sharing resources: Software resources such as file and programs can be shared in a network. Hardware resources such as printers, hard disk and scanners can also be shared in a network.

2. Centralized management: Network help keep information reliable and up to date. A well managed, centralized data storage system allows multiple users to access data from different location.

3. Cost effective: Network allows efficient management of resources. For example, multiple users can share a single high quality printer, rather than having multiple, possibly lower quality printers on individual computer.

4. Security: Network allows authentication before access to any resources in the network. Security can be established at the user level as well as at the resource level.

Type of Networks
Network can be classified as follows:
1. Local Area Network (LAN)
A Local Area Network (LAN) is a network that is confined to a single location, typically one building or enclosed area. The maximum distance from one end of a network to another is usually limited by parameters such as signal strength and cable capacity.

2. Metropolitan Area Network (MAN)
A MAN is a network that covers an entire city, but uses LAN technology. Cable television networks are examples of MAN distributing television signals. MAN haves some components like, Gateways and Routers.

3. Wide Area Network (WAN)
When a network is spread over wide areas, such as across cities, state or countries, it is called a Wide Area Network (WAN). WAN haves some components like, Modem, Brouters and CSU/DSU.


Network Category
The following are the components and features shared by all networks:
1. Servers: Computers that provide shared resources to network users
2. Clients: Computers that access shared network resources provided by a server
3. Media: The way in which the computers are connected

Even with these shared components, network can be divided into two broad categories:
a. Server-Based Networks
Most networks have a dedicated server. A dedicated server is a computer on a network that functions as a server and is not used as a client or a workstation. A dedicated server is optimized to service requests from network clients.
Servers perform a wide variety of tasks. Usually, large network have specialized servers for different tasks. Examples of specialized servers are.
1. File and print servers
2. Application servers
3. Mail servers
4. Communication servers

b. A Peer-to-Peer Network
There is no dedicated server in a peer-to-peer network, and every computer is both a client as well as a server. Resources on the network, such as disk space, printers or faxes, can be shared by anyone who access to the network.

c. Transmission Media
1. Cables
Cable is used as the transmission medium for carrying signals between the computers.
a. Twisted-Pair Cables
b. Coaxial Cable
c. Fiber Optic Cable

2. Wireless
Wireless communication refers to communication through electromagnetic waves
a. Radio
b. Microwave
c. Infrared.


Network Components
1. Modem
A modem is a device that links a computer to other computers through a telephone line. The modem enables a computer to send and receive binary data over a telephone line by changing the bits into sound waves.

2. Bridges
Bridges are devices to connect network segments to each other.

3. Router
A router translates information from one network to another; it can be considered as an intelligent bridge.

4. Hubs
A concentrator is a device that provides a central connection point for cables from workstations, servers, and peripherals.

5. Switch
A switch directs the flow and determines the route of packets as they travel from one segment of a LAN to another.