An Overview of Computer Network Devices & Components
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Fiza Ali December 04, 2006
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A Computer network is comprised of different devices to share,
transmit, and boost the signal, voice and data. Network devices or
components are the physical parts connected to a network. There is a
large number of the network devices and 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. Swith 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
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