LAN topologies: Network topology is a physical schematic that demonstrates interconnection of the many users. There are four fundamental topologies as under:
(i) Direct Connection or one to all topology
(ii) Star topology
(iii) Ring topology
Direct connection or one to one topology:In the one to all topology, there is a path between every node and every other node. Number of paths required is defined by equation P = (n2-n)/2, where n is number of nodes and P, total number of paths. Hence number of paths increases significantly as the number of nodes increases. Every node should be physically able to connect to paths to every other node so a very large connector and associated interface support circuitry is needed at every node. Adding a new node requires major rewiring and affects the software which manages communications for the system.