Hubs

A typical Ethernet LAN uses unshielded twisted-pair (UTP) cables with RJ-45 connectors (which are slightly bigger than telephone RJ-11 connectors). Because these cables have only two ends, you need an intermediary device to connect more than two computers. That device is a hub.

A hub works at Layer 1 and connects multiple devices so that they are logically all on one LAN.

Physical Interfaces and Ports

The physical connection point on a network device—a hub, switch, or router—is called an interface or a port.

Don't confuse this definition of port with the application layer port numbers discussed in the "TCP/IP Transport Layer Protocols" section later in this chapter.

A hub has no intelligence—it sends all data received on any port to all the other ports. Consequently, devices connected through a hub receive everything that the other devices send, whether or not it was meant for them. This is analogous to being in a room with lots of people— if you speak, everyone can hear you. If more than one person speaks at a time, everyone just hears noise.

All devices connected to a hub are in one collision domain and one broadcast domain.

NOTE A hub just repeats all the data received on any port to all the other ports; thus, hubs are also known as repeaters.

Was this article helpful?

0 0
Project Management Made Easy

Project Management Made Easy

What you need to know about… Project Management Made Easy! Project management consists of more than just a large building project and can encompass small projects as well. No matter what the size of your project, you need to have some sort of project management. How you manage your project has everything to do with its outcome.

Get My Free Ebook


Post a comment