Interestingly, Bus and Ring topologies usually look like Stars.

Most Token Ring implementations, for example, make the logical ring look a lot like a star. If you unscrewed the Mau and layed out all the wires, it actually still forms a star, but the network cables congregate in a central point to give the advantages of a Star.

But TallRoo, Why?

  • Why is a Bus bad?
    Well, cut it in the middle and its useless. An no it won't become two smaller busses like some kind of worm-cut-in-half. You need terminators on the end to prevent the bus getting clogged with reflected signals.
  • Why is a ring Bad?
    As with a bus, cut it in the middle and it's broken. To add a new computer you have to break the ring to put a new connection into it. (Clever relays in type 1 Token Ring actually solve this, but you get the idea).
  • Why is a star Good?
    It's not a bus, and it's not a ring. No, seriously, it gives the advantage of central configuration. Plus there's no need to run around the building to add another machine into the network. Just run a cable out from the middle.
  • And, finally Why is a star Bad?
    Of course, one hub also means a single point of failure.
Usually, a combination of different topologies is used.