| A Computer network is comprised of different | | | | SWITCHES: Switch is a intelligence device than hub. |
| devices to share and transmit the data and voice as | | | | Switch is a layer 2 device. Switch provides the same |
| well as to boost the signals. Network devices or | | | | function as a hub or a bridge but it has the advance |
| components are the physical parts connected to a | | | | functionality of connecting the two computers together |
| network. There are a large number of the network | | | | temporarily. Switch contains the switch matrix or |
| devices and, which are increasing daily. The basic | | | | switch fabric that can connect and disconnect ports. |
| network devices are: Individual Computers, Server, Hub, | | | | Unlike hubs, switch only transmit or forwards the data |
| Switch, Bridges, Routers, Modems, Printers, DSL | | | | to the destined computer and it does not broadcasts |
| Modems & Routers, Gateways, Network Interface | | | | the data to all its ports. |
| Cards, Cabling & Wireless access point. The following | | | | MODEMS: Modems are the devices, which are used |
| is a overview of each of these network devices. | | | | to translate the digital data into the analog format and |
| INDIVIDUAL COMPUTERS: The personal computer is | | | | vice versa. It performs the two main functions. |
| usually a desktop computer, a work station or a laptop. | | | | Modulation and demodulation. A modulated data can |
| The personal computers are most widely used in any | | | | travel across the conventional telephone lines. |
| organization or for personal use. The individual | | | | The modem modulates the signals at the sending end |
| computers are the most common types of the | | | | and demodulates at the receiving end. Modems are |
| microcomputers. | | | | required for different types of the access methods |
| SERVER: A server is a computer on a network, | | | | such ISDN, DSL and 56K data modem. Modem can be |
| which process request and is used to share the data | | | | the internal devices that plug into the expansion slots in |
| and resources among the other computers in a | | | | a system or can be external devices that plug into the |
| network. A server stores all the necessary information | | | | serial or USB ports. In Laptops, PCMCIA cards are |
| and provides the different services like, workstation | | | | used for this purpose and many new laptops having |
| computer's logon access, internet sharing, print sharing, | | | | the built in integrated modems. |
| disk space sharing etc. | | | | The specialized devices are designed for use in the |
| There are different types of servers e.g File and print | | | | systems such as handheld computers. In ISPs where |
| server, database server, proxy server, Fax server, | | | | the large scaled modems are required, rack-mounted |
| backup server etc. A database server stores all the | | | | modems are used. |
| data and software, which may related to the certain | | | | ROUTERS: Routers route the data between two |
| database and it allows other network devices to | | | | logically and physically different networks. A Router |
| access and process the database queries. A file | | | | has the capability to determine the destination address |
| server is used to store the data of any user on the | | | | for the data and hence provides the best way for the |
| network and a print server manages one or more | | | | data to continue its journey. |
| printers in a network. Similarly a network server is a | | | | Router gets this capability through its software called |
| server that manages the network traffic. | | | | routing software. Unlike Switches and Bridges, which |
| NETWORK INTERFACE CARD: Network interface | | | | use hardware configured MAC address to determine |
| cards are attached with the computer or other | | | | the destination of the data, router uses logical network |
| network devices and are used to provide the | | | | address such as IP address to make the decision in |
| connectivity between the two computers. Each | | | | determining the destination of the data. |
| network card is specifically designed for the different | | | | GATEWAY: A gateway performs the function of |
| types of the network like Ethernet, FDDI, Token Ring | | | | translating the data from one format to another format |
| and Wireless Networks. The Network card operates | | | | without changing the data itself. A gateway can be a |
| on the first and second layers of the OSI models i.e | | | | device, system, software. |
| Physical layer and datalink layer specifications. NIC | | | | A computer with two NIC cards can function as a |
| basically defines the physical connection methods and | | | | gateway. Router acts as a gateway e.g a router that |
| the control signals that provides the timings of the data | | | | routes the data from a IPX network to a IP network is |
| transfer over the network. | | | | technically a gateway. The same can be said of |
| HUBS: Hub is a simplest network device. The function | | | | translational switch converts from a Ethernet network |
| of the hub is broadcasting i.e data is forwarded | | | | to a token ring network. |
| towards the all ports of a hub, regardless of whether | | | | CABLES: There are two most common types of the |
| the data was intended for the particular systems in the | | | | cables. 1. 10baseT and 10base2. 10baseT is a four |
| network or not. Computers in a network are | | | | paired cable. 10baseT has further two types 1. UTP |
| connected to a hub with a twisted pair (CAT5) cables. | | | | (unshielded twisted pair) and 2. STP (shielded twisted |
| There are two types of the hubs. 1. Active Hubs. 2. | | | | pair. STP is most secure cable covered with the silver |
| Passive Hubs. | | | | coated twisted paper to protect the cable. |
| SWITCHING HUB: The Switching hub (also called | | | | On the other end Thin 10base2 looks like the copper |
| "switch" is the most advance shape of the basic hub. | | | | coaxial cabling that often used to connect TV sets |
| In a basic hub all the computers are connected with | | | | and VCR. 10baseT/Cat5 cables are most commonly |
| the hub and the speed of the network is defined by | | | | used cables to connect the computers. It has the |
| the slowest computer network card connected. For | | | | connector, (like a telephone connector) called RJ45 |
| example if you have 10/100 Mbps cards in a network | | | | connector. |
| and only one card of 10Mbps speed then the system | | | | Twisted pair cables are ideal for the small, medium or |
| cannot run faster than the 10 Mbps. Now if you have a | | | | large networks. |
| switching hub in a network, it will allow all the faster | | | | My recommendation for using cables for networking is |
| connections in the network to remain at the higher | | | | to use 10baset/Cat5 cables. |
| speed and still interact with the 10Mbps system. | | | | |