NETWORK DEVICES

                                      NETWORK DEVICES

 SWITCH:--
A network switch (or just switch) is a networking device that
performs transparent bridging at up to the speed of the
hardware. Common hardware includes switches, which can Neo
connect at 10, 100, or 1000 megabits per second, at half or
full-duplex. Half-duplex means that the device can only send
or receive any given time, whereas full-duplex can send and
receive, at the same time. Switches can be used in place of
hubs.
When the network is expanded to adjust to new users and more sophisticated applications, the amount of
information being sent may exceed the amount of information, the network was originally designed to
handle. This can cause congestion and a reduction in the performance of the network. Replacing the
hubs on an overloaded network with switches can increase the efficiency of the network. When you
replace hubs with switches, you usually do not have to replace other elements of the network, such
as the cable system.
Security: 
Switches can help ensure that the information users shift over a network is secure. Unlike a
hub, which transfers information to every computer on the network segment, a switch sends data to
the intended recipient only.

ROUTING SWITCHES:---

 Some switches, called routing

switches, have capabilities that are similar to those of a

fouter

. Routing switches can direct or route information to

the intended destination on a network. Routing switches

may also be able to find the most efficient route for

Information to transverse,

REPEATERS:--

A repeater is an electronic device that receives a weak or low-level signal

and retransmits it at a higher level or higher power, so that the signal can

cover longer distances without degradation. They are used to interconnect

segments in LANs and to extend WAN transmission.

The signal will become weaker, the more it travel along a cable. This is often referred to as

attenuation. Repeaters prevent problems that might result from weak signals by strengthening the

signal.

Repeaters are used to extend the length of the cables that connect computer devices together on a

network. Repeaters are especially useful in areas where long lengths of cable are required to connect

computer devices together, such as a network in a large warehouse.

BRIDGES:--

A device that connects two networks into one large logical

network so that information can flow between them.

Bridges are helpful in connecting a small number of individual networks to make them work together as

one large network. A network comprising smaller networks is called internetwork.

Bridges are also helpful in breaking a busy network into smaller segments. Breaking a busy network is

helpful in reducing excess network traffic. For example, if the computers in one department generate a

lot of network traffic, a bridge can separate that department from the rest of the network.

ROUTER:--

A router is a computer networking device that forwards

ROUTER

data across a network toward their destinations, through a

a process is known as routing.

Router

A router acts as a junction between two or more networks to transfer data packets among them. A

router is different from a switch. A switch connects devices to form a local area network (LAN). One

easy illustration for the different functions of routers and switches is to think of switches as

neighborhood streets, and the router as the intersections with the street signs.

A large network may have more than one route that

information can take to its intended destination.

There are some routers that can automatically detect if

a part of the network is malfunctioning or is slow. The

routers will try to redirect information around the problem

area so the impact of the network failure will be minimal.

Routers are said to be intelligent because they can analyze a network to determine the best router for information to take.

TYPE OF ROUTER:-

 Most routers can automatically determine the best route for information.

With older routers, called static routers, a network administrator had to manually configure the router

to recognize each route information could take. Newer routers, called dynamic routers, automatically

create and maintain a table of the available routes on the network.

Wide Area Network (WAN):

 Routers are helpful in connecting local area networks to a wide

area network. Routers are also helpful in splitting a wide area network into segments. This helps reduce

the amount of information being transferred over the network and improves the efficiency of the WAN.

NETWORK COMMUNICATION TECHNOLOGY

Now a days, networking is established by connecting terminals, devices and computer across WAN,

LAN and wireless.

Ethernet

Ethernet is a LAN technology and the most popular and least

expensive mode of transferring information through a network. It

is the easiest type of network to set up. It is based on a bus

topology, but Ethernet network can be wired in a star pattern.

When ethernet works, each computer waits for a fraction of time

before sending the information through a network. When two

computers try to send information at the same time, a collision

occurs. After a moment, the computers resend the information.

Ethernet can transfer information through a network at a speed of 10 megabits per second (Mbps).

Fast Ethernet can transfer information through a network at a speed of 100 Mbps. Gigabit Ethernet is

a type of Ethernet that can transfer information through a network at a speed of 1000 Mbps.

Ethernet cable

Token-ring

tohet ding is a type of LAN technolory network that is often found in large organizations, such 

hands and insurance companies. A token ring network can send information through a network at

speeds of 4 or 15 Mbps,

Working of Token-ring:

 Token ring works by

passing a single token from computer to computer,

The token collects and delivers information as it travels

around the network. When any computer on the

network wants to send data, it takes control of a free

token. The computer can then transmit data. Until the

token has been released by the computer that is

seading data, no other computer can transmit. As only

one computer can use the token at a time, the

possibility of a collision is ruled out

TCP/IP (Transmission Control Protocol / Internet Protocol)

TCP/IP breaks up data into small packet for every transmission Internet transmissions commonly use

TCPIR. When a computer sends data over the internet, the data is divided into small pieces, or

packets. Each packet contains the data, as well as the recipient (destination), origin (sender) and the

sequence information for reassembling the data at the destination. These packets travel along the

Tastest available path to the recipient's computer via devices called routers

. Thus, this technique of

transmitting package from source to destination along the best possible route is called pocket

switching

WAP

WAP or Wireless Application Protocol is an open international standard for applications that use

wireless communication. Its principal application is to enable access to the Internet from a mobile

phone or PDA. A WAP browser is designed to provide all of the basic services of a computer-based

web browser but simplified to operate within the restrictions of a mobile phone. WAP is now the

protocol used for the majority of the world's mobile internet sites, known as WAP sites.

INTRANET

A private network that is based on Internet protocols such as TCP/IP but designed for information

management within a company or organization. It includes services such as document distribution,

software distribution, and access to databases. It is called intranet as it looks like a World Wide

Website and is based on the same technologies, yet is strictly internal to the organization and is not

connected to the Internet proper. Some intranets also offer access to the Internet, but such

connections are directed through a firewall that protects the internal network from the external Web.

Sometimes a company uses an extranet, which allows customers or suppliers to access part of its

intranet. Some banks, for example, allow their customers to access their intranet to know and print

their account balance and other services.