In other words, to hook all your computers together, a special electronic circuit card called a NIC goes inside each computer. That's where you plug in the cable that connects the computer to the network. You will find that NICs vary in cost depending on the type of protocol they support. For example, 10BaseT NICs are inexpensive when compared to FDDI NICs. A hub is a device that serves as the center of a star topology network like 10BaseT. It is also called a concentrator.
Stackable hubs have a fixed number of ports available to connect network devices.
Modular hubs offer a great deal of flexibility. It is possible to have an Ethernet network, AppleTalk network, and token ring network running in the same hub. Greater flexibility also translates into higher costs, and modular hubs do cost more. Intelligent hubs keep track of information about the data that passes through them. They provide basic management capabilities, while nonintelligent hubs do not.