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A Computer network is comprised of different devices to share and transmit the data and voice as well as to boost the signals. Network devices or components are the physical parts connected to a network. There are a large number of the network devices and, which are increasing daily. The basic network devices are: Individual Computers, Server, Hub, Switch, Bridges, Routers, Modems, Printers, DSL Modems & Routers, Gateways, Network Interface Cards, Cabling & Wireless access point. The following is a overview of each of these network devices.

INDIVIDUAL COMPUTERS: The personal computer is usually a desktop computer, a work station or a laptop. The personal computers are most widely used in any organization or for personal use. The individual computers are the most common types of the microcomputers.

SERVER: A server is a computer on a network, which process request and is used to share the data and resources among the other computers in a network. A server stores all the necessary information and provides the different services like, workstation computer's logon access, internet sharing, print sharing, disk space sharing etc.

There are different types of servers e.g File and print server, database server, proxy server, Fax server, backup server etc. A database server stores all the data and software, which may related to the certain database and it allows other network devices to access and process the database queries. A file server is used to store the data of any user on the network and a print server manages one or more printers in a network. Similarly a network server is a server that manages the network traffic.

NETWORK INTERFACE CARD: Network interface cards are attached with the computer or other network devices and are used to provide the connectivity between the two computers. Each network card is specifically designed for the different types of the network like Ethernet, FDDI, Token Ring and Wireless Networks. The Network card operates on the first and second layers of the OSI models i.e Physical layer and datalink layer specifications. NIC basically defines the physical connection methods and the control signals that provides the timings of the data transfer over the network.

HUBS: Hub is a simplest network device. The function of the hub is broadcasting i.e data is forwarded towards the all ports of a hub, regardless of whether the data was intended for the particular systems in the network or not. Computers in a network are connected to a hub with a twisted pair (CAT5) cables. There are two types of the hubs. 1. Active Hubs. 2. Passive Hubs.

SWITCHING HUB: The Switching hub (also called *switch* is the most advance shape of the basic hub. In a basic hub all the computers are connected with the hub and the speed of the network is defined by the slowest computer network card connected. For example if you have 10/100 Mbps cards in a network and only one card of 10Mbps speed then the system cannot run faster than the 10 Mbps. Now if you have a switching hub in a network, it will allow all the faster connections in the network to remain at the higher speed and still interact with the 10Mbps system.

SWITCHES: Switch is a intelligence device than hub. Switch is a layer 2 device. Switch provides the same function as a hub or a bridge but it has the advance functionality of connecting the two computers together temporarily. Switch contains the switch matrix or switch fabric that can connect and disconnect ports. Unlike hubs, switch only transmit or forwards the data to the destined computer and it does not broadcasts the data to all its ports.

MODEMS: Modems are the devices, which are used to translate the digital data into the analog format and vice versa. It performs the two main functions. Modulation and demodulation. A modulated data can travel across the conventional telephone lines.

The modem modulates the signals at the sending end and demodulates at the receiving end. Modems are required for different types of the access methods such ISDN, DSL and 56K data modem. Modem can be the internal devices that plug into the expansion slots in a system or can be external devices that plug into the serial or USB ports. In Laptops, PCMCIA cards are used for this purpose and many new laptops having the built in integrated modems.

The specialized devices are designed for use in the systems such as handheld computers. In ISPs where the large scaled modems are required, rack-mounted modems are used.
ROUTERS: Routers route the data between two logically and physically different networks. A Router has the capability to determine the destination address for the data and hence provides the best way for the data to continue its journey.

Router gets this capability through its software called routing software. Unlike Switches and Bridges, which use hardware configured MAC address to determine the destination of the data, router uses logical network address such as IP address to make the decision in determining the destination of the data.

GATEWAY: A gateway performs the function of translating the data from one format to another format without changing the data itself. A gateway can be a device, system, software.

A computer with two NIC cards can function as a gateway. Router acts as a gateway e.g a router that routes the data from a IPX network to a IP network is technically a gateway. The same can be said of translational switch converts from a Ethernet network to a token ring network.

CABLES: There are two most common types of the cables. 1. 10baseT and 10base2. 10baseT is a four paired cable. 10baseT has further two types 1. UTP (unshielded twisted pair) and 2. STP (shielded twisted pair. STP is most secure cable covered with the silver coated twisted paper to protect the cable.

On the other end Thin 10base2 looks like the copper coaxial cabling that often used to connect TV sets and VCR. 10baseT/Cat5 cables are most commonly used cables to connect the computers. It has the connector, (like a telephone connector) called RJ45 connector.

Twisted pair cables are ideal for the small, medium or large networks.

My recommendation for using cables for networking is to use 10baset/Cat5 cables.

Regards

Fiza