The data communication system includes many devices for various purposes. Let us discuss some of the important devices used in the context of network.
1.Repeater
In local computer networks the transmission media used is coaxial cable or twisted pair cable. Any media will attenuate (degradation of signal will passing through any communication media) signals passing through them, thus reducing signal strength. This problem limits the distance any media can carry data. Let us consider the case of interconnecting two computers or computer networks, which are more than 100m apart. In this case we must use a repeater in between them. The repeater will amplify the signals passing through it, thus increasing data communication distance.
Repeater are two types
1. Amplifier type
2. Signal re-generator type
As the name implies the amplifier type repeater will just amplify the signals and re-transmits it. Main problem associated with this type of repeaters is that it will reduce signal quality. In signal re-generator type, repeaters exact duplicate of data received is generated and the new data packets are re-transmitted.
So how to define a repeater ?
Repeater is a device that compensate for signal attenuation while traveling through a media, thus increasing signal transmission distance.
2.Bridge
Generally we can define a bridge as a device having two or more ports that connects local area networks (LAN's) and forwards data packets between them.
Let us consider each network as a segment. A repeater will just amplify and re-transmit the signal. But in the case of a bridge, if multiple segments are there, then each data packet received is analyzed and is properly routed to the segment where the addressed computer resides.
So how to define a bridge ?
Bridge is device that connects multiple network segments, regardless of their wiring topology. Also they are capable of intelligently routing packets to the segment containing destination computer only.
So how to define a repeater ?
Repeater is a device that compensate for signal attenuation while traveling through a media, thus increasing signal transmission distance.
2.Bridge
Generally we can define a bridge as a device having two or more ports that connects local area networks (LAN's) and forwards data packets between them.
Let us consider each network as a segment. A repeater will just amplify and re-transmit the signal. But in the case of a bridge, if multiple segments are there, then each data packet received is analyzed and is properly routed to the segment where the addressed computer resides.
So how to define a bridge ?
Bridge is device that connects multiple network segments, regardless of their wiring topology. Also they are capable of intelligently routing packets to the segment containing destination computer only.
3.Routers
Routers are inter networking devices. I.e., they are devices that connect two or more networks. Basically router is a combination of hardware and software. The hardware part includes the interface between various networks and main components of software are operating system and routing protocol.
4.Gateway
To connect totally different networks a device called gateway is used. The network need not be a computer network. For example we can connect to the internet through dial up connection using ordinary phones.A gate way is used for connecting PSTN(Public Switched Telephone Networks) network to the internet. A gate way is used for connecting computer networks that runs different operating systems. In general a gate way handles messages addresses and protocol conversions necessary to deliver a message from one network to another.
Depending on various networks different types of gateways are there, like IBN gateways. LAN gateways, Email gateways. Internet gateways etc.
Routers are inter networking devices. I.e., they are devices that connect two or more networks. Basically router is a combination of hardware and software. The hardware part includes the interface between various networks and main components of software are operating system and routing protocol.
4.Gateway
To connect totally different networks a device called gateway is used. The network need not be a computer network. For example we can connect to the internet through dial up connection using ordinary phones.A gate way is used for connecting PSTN(Public Switched Telephone Networks) network to the internet. A gate way is used for connecting computer networks that runs different operating systems. In general a gate way handles messages addresses and protocol conversions necessary to deliver a message from one network to another.
Depending on various networks different types of gateways are there, like IBN gateways. LAN gateways, Email gateways. Internet gateways etc.
Another important thing in network communication is Its Backbone Network. It cannot included in networking Devices category. But it is inevitable.
Backbone network
Let us consider case of a building or campus that have many local area networks. In such cases it is necessary to interconnect these scattered networks. Most important thing is the communication link used for interconnecting these networks should have sufficient bandwidth. A backbone is the part of network used for interconnecting multiple networks. Usually high bandwidth optic fiber cables are used as backbone networks. Backbone networks are also used for connecting Wide Area Networks (WANs). But the installation cost of backbone networks having large bandwidth will be very high. The communication efficiency between computer networks depends mainly on the bandwidth and speed of backbone network.
Backbone network
Let us consider case of a building or campus that have many local area networks. In such cases it is necessary to interconnect these scattered networks. Most important thing is the communication link used for interconnecting these networks should have sufficient bandwidth. A backbone is the part of network used for interconnecting multiple networks. Usually high bandwidth optic fiber cables are used as backbone networks. Backbone networks are also used for connecting Wide Area Networks (WANs). But the installation cost of backbone networks having large bandwidth will be very high. The communication efficiency between computer networks depends mainly on the bandwidth and speed of backbone network.
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