Difference between hub and switch ?

[KABIRA]

I want to connect 25 pc in my office. I am confusing about switch and Hub. Can you tell me what is difference between hub and switch ?

Thanks

[HADLEY]

Although hubs and switches both glue the PCs in a network together, a switch is more expensive and a network built with switches is generally considered faster than one built with hubs.

[Samk]

A switch does essentially what a hub does but more efficiently. By paying attention to the traffic that comes across it, it can learn where particular addresses are. For example, if it sees traffic from machine A coming in on port 2, it now knows that machine A is connected to that port and that traffic to machine A needs to only be sent to that port and not any of the others. The net result of using a switch over a hub is that most of the network traffic only goes where it needs to rather than to every port. On busy networks this can make the network significantly faster.

[hayeden]

A hub is typically the least expensive, least intelligent, and least complicated of the three. Its job is very simple: anything that comes in one port is sent out to the others. That's it. Every computer connected to the hub everything that every other computer on the hub sees. The hub itself is blissfully ignorant of the data being transmitted. For years, simple hubs have been quick and easy ways to connect computers in small networks.

[Bradan]

Two computers can be connected directly together in an Ethernet with a crossover cable. A crossover cable doesn't have a collision problem. It hardwires the Ethernet transmitter on one computer to the receiver on the other. Most 100BASE-TX Ethernet Adapters can detect when listening for collisions is not required with a process known as auto-negotiation and will operate in a full duplex mode when it is permitted.