Networks can be arranged into well-defined structures, known as topologies, that display certain characteristics.
Point to point
Point to point networks directly connect two hosts together.
Bus networks connect all hosts using T-taps off of a single wire serving as a backbone. All devices receive all messages as a series of +/- 5 volt pulses.
When multiple devices attempt to transmit concurrently, the network interfaces on the hosts identify the 10 volts on the wire and wait a random amount of time before attempting to retransmit, backing off to avoid collisions.
In a ring network all of the hosts are connected to a single cable ring. A single token is passed sequentially between all hosts, giving them an opportunity to both read and write data while they hold it.
This model was popular with IBM networks, with a MAU serving as a central hub between all hosts.
This topology is the basis of smaller Ethernet networks, where all hosts are connected to a central hub or switch via point to point connections.
Tree networks are comprised of a series of star networks arranged into a hierarchical structure, connected to a linear bus backbone/
In a mesh network all devices are directly connected, much like a multi-host point to point network. The types of links between hosts vary:
- Simplex links can only transmit one-way
- Duplex links are two-way.