What is a Computer Network?

A computer network is a collection of computing devices that are connected with each other for the purpose of information and resource sharing among a wide variety of users.

A system of interconnected computers and computerized peripherals such as printers is called computer network. This interconnection among computers facilitates information sharing among them. Computers may connect to each other by either wired or wireless media.

Features of Computer Network

The features of a computer network are −

• Sharing − Computer networks enable sharing of files, software, hardware resources and computing capabilities.
• Speed: The communication speed among the components is fast enough to be comparable with a centralized system.
• Scalability − Sizes of computer networks dynamically increase with time. The networks have to be scalable so that they can evolve adequately for future deployments.
• Integration − All the components of the network work in a coordinated manner for a seamless user experience.
• Security − Networks allow security and access rights to the users for restricted sharing of resources and information.
• Cost Effectiveness − Networking reduces the deployment cost of hardware and software of a centralized system.

Classification of Computer Networks

Computer networks are classified based on various factors.They includes:

• Geographical span
• Inter-connectivity
• Administration
• Architecture

Geographical Span

Geographically a network can be seen in one of the following categories:

• It may be spanned across your table, among Bluetooth enabled devices,. Ranging not more than few meters.
• It may be spanned across a whole building, including intermediate devices to connect all floors.
• It may be spanned across a whole city.
• It may be spanned across multiple cities or provinces.
• It may be one network covering whole world.

Inter-Connectivity

Components of a network can be connected to each other differently in some fashion. By connectedness we mean either logically , physically , or both ways.

• Every single device can be connected to every other device on network, making the network mesh.
• All devices can be connected to a single medium but geographically disconnected, created bus like structure.
• Each device is connected to its left and right peers only, creating linear structure.
• All devices connected together with a single device, creating star like structure.
• All devices connected arbitrarily using all previous ways to connect each other, resulting in a hybrid structure.

Administration

From an administrator’s point of view, a network can be private network which belongs a single autonomous system and cannot be accessed outside its physical or logical domain.A network can be public which is accessed by all.

Network Architecture

Computer networks can be discriminated into various types such as Client-Server,peer-to-peer or hybrid, depending upon its architecture.

• There can be one or more systems acting as Server. Other being Client, requests the Server to serve requests.Server takes and processes request on behalf of Clients.
• Two systems can be connected Point-to-Point, or in back-to-back fashion. They both reside at the same level and called peers.
• There can be hybrid network which involves network architecture of both the above types.

Network Applications

Computer systems and peripherals are connected to form a network.They provide numerous advantages:

• Resource sharing such as printers and storage devices
• Exchange of information by means of e-Mails and FTP
• Information sharing by using Web or Internet
• Interaction with other users using dynamic web pages
• IP phones
• Video conferences
• Parallel computing
• Instant messaging