In a machine topology, each computer is connected to each other by a separate cable. This configuration provides redundant paths in the network, so if one cable fails, another cable takes over the traffic and the network continues to function smoothly. For larger systems, multiple LANs can be connected with a machine topology. Leased telephone lines, ThickNet coaxial cables or fiber optic cables were used for this purpose. One advantage of the machine topology is its backup capability, as several paths are provided in the network. Since redundant paths require more cables than other topologies, a machine topology can be expensive.