COMPUTER NETWORKS

WHAT ARE NETWORKS

A computer network is a system for communication among two or more computers. Networks interconnect computer systems at various different sites allowing them to exchange information such as file sharing, internet connection and data storage.

Basically, a network is two or more machines connected together by some type of medium such as Ethernet, Token Ring and Wireless.

TYPES OF NETWORKS

There are three basic types of computer networks commonly use i.e. Ethernet, Token Ring and Wireless.

ETHERNET

Ethernet is the most popular standard ffor most computer network connections. There have been many kinds of Ethernet but the most popular and frequently use is 10/100Mbps running over copper twisted pair wires. 100Mbps Ethernet is also called 100baseT and Fast Ethernet. This is pretty fast connections between 10/100 Ethernet adapters are made using cables that run to an Ethernet HUB or Switch. HUBs electrically connect your computers together and Switches act like traffic cops making your network more efficient.

Example of an Ethernet connections are as pictured (left).

TOKEN RING

The Token Ring is a type of computer network in which all the computers are arranged (schematically) in a circle. A Token, which is a special bit pattern, travels around the circle. To send a message, a computer will catches the token, attaches a message to it and then lets it continue to travel around the network.




The Token Ring network is an older and less commonly used. Although it is considered a more reliable system, a Token Ring network is slower and offers less flexibility especially in today businesses. In a Token Ring, only one computer may send information at a time.






WIRELESS


Wireless networks are telephone or computer networks that use radio waves as their carrier or physical layer. Wireless networking allows the user to have the same access to the network as people with a traditional wired network but with the freedom to move anywhere within approximately 100 feet of the Wireless signal.


There are many different standards of Wireless access but the most commonly used and most dependable is WiFi ( is also known as 802.11 networking). The big advantage of WiFi is its simplicity. WiFi allowed you to connect computers anywhere in home or without ( within allowable range) without the need of wires.


Above is the example of a Wireless network. The blue box is a Wireless router that is connected by a cable to a modem. The Wireless router turns the network signal into a radio waves which can be received by anu wireless device within 100 feet ( or more depends on the technology adopted).

NETWORKING TERMINOLOGY

Belows are some of the terminology commonly found :

Backbone
Cables that interconnect hubs and switches.

Ethernet
Refers to the family of local-area network (LAN). Three data rates are currently defined for operation over optical fiber or twisted-pair cables i.e. 10 Mbps, 100 Mbps and 1000 Mbps.

Fiber
Strands of optically pure glass (very thin) that carry digital information over long distances.

Gigabit / Megabit
Amount of memory. 1 gigabit equal to 1024 megabits (1,073,741,824 bits)

Hub
A common connection point for devices in a network.

LAN
Local area network. A local computer network for communication between computers within a smal geographical distance.

Server
A computer software application that carries some task. Web, mail and database servers are what most people access when using the internet.

Switch
A fundamental part of many networks because they speed things. Switches allow different nodes (a network connection point) to communicate directly with one another in a smooth and efficient manner.

Tape Library
An automated library used to store massive amounts of information on magnetic tape catridges.

WAN
Wide area network is a computer network covering a wide geographical area, involving vast array of computers. The best example of WAN is internet.