Tuesday, 21 June 2011

What is the difference between a switch and a hub?

What is the difference between a switch and a hub?

The Hub


A hub is a small device that connects multiple computers together. A hub is the least expensive, least intelligent and least complicated as compared to a switch. In small computer networks, the hub is an easy and fast device to connect computers. In a hub, the information that comes from one port is sent out to other computers from a second port. The hub works on the physical layer of the OSI model. It operates by using the broadcast model. In a hub network, only one collision domain is used. Hubs accept a single data packet and then send it out to all the connected computers. In a hub network, only one data packet travels at a time while the others wait for their turn. In such a network, the bandwidth is divided by all the computers, causing a slowdown. For this reason, data collisions are very common in hubs. For example, if six computers are communicating with each other and the hub sends data to all the six, then only two of the six computers communicate with one another.

The Switch


It is a small network hardware device that connects multiple computers together within one local area network (LAN). A switch is a network device that selects a path for sending data to its next destination. A switch works more efficiently than a hub. It works faster on busy networks. A network built with switches is faster than the one built with hubs. The switch works on data link layer of the OSI model. Switches operate by using a virtual circuit model. Switches maintain MAC address tables. In switch networks, the networks divide into multiple collision domains. There is no collision of data in a switch network, and therefore, the speed is high. A switch does not broadcast data to all the computers in the network. It operates like a bridge between two computers. In a switch network, multiple paths exist at the same time. For example, if six computers communicating with each other are connected to a switch, then data is exchanged between two computers only.

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