The difference among Hub, Bridge, Switch and Router

These are most common words uttered when we talk about network. Sometime we confuse our self which for what. This is because all the four have some similarity but they are not same. To understand a network we need understand about their working principle.

Hub

It is the least expensive and intelligent network device compared with others and in modern days not used too much. It has a very simple working principle. It just passes the information packet to all. Not sense anything, not take any decision.

For an example suppose five computers are connected through Hub in a LAN network. If No 1 computer transmit a packet of information to no 3 computers then Hub just pass all the information to all four computers. It is then up to computers to decide whether it will take the packet or not.

This simplified operation creates unnecessary traffic and make the network slow.

Bridge

As the name suggest bridge links two points. It is upgraded version of Hub that just not passes information but also take some decision. Bridge has only two ports. Normally bridge is used to link two networks. It has the capability of taking decision whether the information should go other side or not. It can sense both side destination and find out whether the destination is in the same side or on the other side. If it is on the same side then bridge does not allow the information to pass through it hence reduce traffic. It can be used to link two networks where traffic between them is low.

Normally two types of bridge used. Transparent bridges are used to link two same type of Network where Translation bridges are used to link to different Network.

Switch

Switch is the upgraded version of bridge with multi port support and content addressable memory.  With this Content addressable memory (CAM) a Switch can easily find out the correct destination and send the data packet only to it. It increases the performance dramatically.

A switch always maintains dynamic CAM. Whenever a network device connected through it port it save the devices MAC address in its CAM table. So it always knows the addresses of all connected device. Hence it becomes easy for a switch to take decision where the packet will go.

Router

Router works a little bit different from others. As its name suggest it finds the best possible way or route for your message to go its destination. For this router use IP address instead of MAC address and also can surf through different protocols.