Networking: A Beginner's Guide
other nodes must contend with that use for their own. In other words, if you're using a
network type with a capacity of 100 Mbps, that's the total amount of bandwidth available
to all of the nodes connected to the hub.
NOTE Networks that are physically wired in a star topology are logically either a bus or a ring.
This means that, despite what the network looks like, it still "behaves" as either a bus or a ring.
Ethernet networks wired in a star fashion are logically a bus. Token Ring networks wired in a star
fashion are logically a ring.
Star topology networks can use one of several forms of Ethernet. The most common
is 100Base-T Ethernet, which provides 100 Mbps of bandwidth. Quite a few older
networks use 10Base-T Ethernet, which provides 10 Mbps of bandwidth. A newer
standard called Gigabit Ethernet (1000Base-T) offers 1 Gbps of bandwidth. Most
recently, a standard called 10 Gigabit Ethernet (or alternately 10GBase-X), which can
run at 10 Gbps over fiber-optic cable, has been approved.
10Base-T requires a type of twisted-pair cable called Category 3 (Cat-3) cable.
100Base-T requires Category 5 (Cat-5) cable. 10Base-T can also use Cat-5, but 100Base-T
cannot use Cat-3. These days, you should always use the most recent Cat-5 cable--
called Cat-5E--even if it's intended for only a 10Base-T network. (Cat-5 cable provides
eight wires--four twisted pairs--and so can carry two connections in each cable if
desired.) If cost is not an issue, consider even moving up to Cat-6.
10Base-T networks share the following wiring characteristics:
Require four actual wires (two twisted pairs in a single sheath); can be either
unshielded twisted-pair or shielded twisted-pair
Can be run on either Cat-3 or Cat-5 cable
Are limited to a length of 100 meters (328 feet) for each node connection
A star topology network