)The shape of a local-area network (LAN) or other communications system. Topologies are either physical or logical.
There are four principal topologies used in LANs.
These topologies can also be mixed. For example, a bus-star network consists of a high-bandwidth bus, called the backbone, which connects a collections of slower-bandwidth star segments.
For network diagrams, see Network Topology Diagrams in the Quick Reference section of Webopedia.