whether you intend to use either hubs or switches. Hubs and switches are
visually the same in that they have rows of network ports. However, under the
hood, the difference is quite important. Data is sent as packets of information
across the network; with a hub, the data is transmitted simultaneously to all
the network ports, regardless of which port the destination computer is
attached to.
Switches, however, are more intelligent because they can direct packets of
information to the correct network port that leads to the destination computer.
They do this by “learning” the MAC addresses of each computer that is
attached to them. In short, using switches minimizes excess packets being
sent across the network, thus increasing network bandwidth available. In a
small network with a handful of computers, the use of hubs might be perfectly
acceptable, and you will find that hubs are generally cheaper than switches.
However, for larger networks of 15 computers or more, you should consider
implementing a switched network.
TIP
Troubleshooting network connections can be challenging, especially on
large networks. If a user complains that he has lost his network connection,
examining the hub or switch is a good place to start. If the link light for the
user’s port is lit, chances are the problem is with the user’s network
configuration. If the link light is not on, the host’s NIC is bad, the cable is
not inserted properly, or the cable has gone bad for some reason.Routers and Bridges
Routers and bridges are used to connect different networks to your network
and to connect different subnets within your network. Routers and bridges
both serve the same purpose of connecting networks and subnets, but they do
so using different techniques. The information in the following sections helps
you choose the connection method that best suits your needs.
Bridges
Bridges are used within a network to connect different subnets. A bridge
blindly relays all information from one subnet to another without any filtering
and is often referred to as a dumb gateway. This can be helpful if one subnet
in your network is becoming overburdened and you need to lighten the load.
A bridge is not very good for connecting to the Internet, however, because it
lacks filtering. You really do not want all traffic traveling the Internet to be
able to get through to your network.