Ethernet: Collision domain of a Network Hub...(What Does this Mean?)

Any message recieved on a hub gets transmitted out on all ports (therefore: Collision domain of a Network Hub is ALL ports of the hub). A switch has the brains to take an incoming message and route it to ONLY the specific port that has the destination IP connected to it (therefore: Collision domain of Network Switch is a SINGLE port).

A hub is nothing more than a joining of all the cables from all the ethernet devices which are connected on that section of the network.In other words it cannot differentiate the signals going to any particular computyer.

A switch on the other hand creates "small sub-networks " based on the IP addresses on the message.

In this way when the header frame is sent ahead of the message, the switch quickly reads the destination addresses and creates a virtual private connection between the two devices so the collision domain is reduced.