Friday, September 11, 2009

Unsielded Twisted Pair Cable ( UTP)

Twisted pair of cable is just what its name implies insulated wires with a minimum number of twists per foot. Twisting the wires reduces the electricla interference. Unshielded twisted pair is very familiar type of cable. It is often used as the telephone cable.

UTP cables comes is variety of grades called level 5, level 4 and level 3, offering better perpormance than an ordinary telephone cable. Level 5 cable is the highest most expensive grade, meant for 100mbps networks. Level 4 and level 3 cables are less expensive, but cannot support the same data throughput speeds. Level 4 cable can support upto 20 mbps and level 3 upto only16mbps.

This wide variety of cables shows the evolution of the ethernet technology. Thick coax was one of the cabling systems used in the ethernet but was difficult to work with and expensive. This lead to the development of the thin coax, which is easier to work with and less expensive. Today the most popular cable is unshielded twisted pair ( UTP ) Cable. This looks like a telephone cable but comes in variety of grades.

Coaxial cable

Coaxial cabel is easily identified in your every day life. You always find it connected to the television sets and audio equipment. Thick and thin refer to the diameter of the coaxial cable standard ethernet cable ( thick coax) is over a centimeter in diameter. The thin coax is about half of thick coax in diameter. the thick coax has a greater degree of noise immunity and is quite strong. This network. Though thin coax carries signal over the shorter distance, it is perferred over thick coax, because thin coax needs simple BNC connecter and is very flexible and is cheaper than the thick coax and more flexible and soft and ideal for office cabling environment

Sunday, September 06, 2009

Components of a computer network

A network is a combination of different components. The most essential components of a simple network are:

Servers: Servers are the faster computers to run various softwares,stores and process information and to provide a human interface for the users to be able to use the networked computers.

Nodes: Nodes are the computers on the network which are provided to the users to carry out their task using the network.A node which is more powerful and can handle local information processing or graphics processing is called workstation.

The workstation works only for the person sitting in front of it. whereas a server serves all the people on the network to share its resources. A workstation usually has an inexpensive, small hard disk to carry out local tasks. Some workstations, called disk less workstations, have no disk drive of their own. Such workstations also called dumb terminals, rely completely on the LAN for their access. The network operating system Lets the nodes work as if all the resources at the server belong to the Node itself.

LAN cables: This is the medium over which the information travels from computer to computer. from the computer onto the medium and to take up the information from the medium and make it available to the computer in the form it can read.

Network Operation system Software: to control the movement of information on the network.
Networks which are more complex, require components like hubs, on the network, each computer is called a node or a workstation unless there are certain computers designed as servers. Each computer contains a network interface card. Lan cables connect all the node sand severs together to form the network. in addition to its local disk operation system each node requires a networking software the enables the nodes to communicate with the servers. In return the files servers run network software the communicate with nodes.