The mapping of a LAN design is called Topology. There are four categories:
- Star topology
- Bus topology
- Ring topology
- Mesh topology
Hybrid combinations of these topologies also exist.
- Star topology – all computers and devices are connected to a main hub or switch. The hub or switch amasses and disburses the flow of data within the network. Star topology is the most common type of network and follows the Ethernet standard.
- Bus topology – in this arrangement computers and devices are connected to a single linear cable called a trunk. The trunk is also referred to as the backbone or a segment. Each end of the trunk must be discharged to prevent the signal from rebounding back up the cable.
- Ring topology – computers and devices are connected to a closed loop cable. Here there are no terminating ends so if one system crashes the entire network goes down. Each computer functions as a repeater and charges the signal before sending it to the next station. In Ring topology data is sent through the network by way of a token. If the token isn’t carrying any data, a computer waiting to send data seizes it, attaches the data and the electronic address to the token and sends it on. Once the token is received by the destination computer it strips the data and the token is sent on. This is why it’s named a token ring network.
- Mesh topology – all computers and devices are connected with many repeated interconnections between network nodes. There are two types: full mesh and partial mesh. With full mesh topology every computer or device has a link that connects it to every other computer or device in a network. This form of mesh topology is expensive but offers a high amount of redundancy should one of the nodes fail. If this occurs network traffic can be redirected to any of the other nodes. Full mesh is usually reserved for backbone networks. Partial mesh topology takes some of the devices and configures them in a full mesh scheme while other devices are connected to only one or two other devices in the network. Partial mesh topology is less expensive to put in place and offers less redundancy than full mesh topology. Partial mesh is typically found in sub networks connected to a fully meshed backbone.
