Method and apparatus for enhanced routing within a shortest path based routed network containing local and long distance links

摘要

Use of a Location ID in addition to normal information to allow development of non-shortest path routes. The edge switches which terminate the distance links between locations are identified. Shortest path routes are determined for all switches in the same location. For each edge switch, routes over the distance links to other locations are determined, marking the interface connected to the distance links. The two determined sets of routes are combined. For devices directly connected to the edge switch, only the marked interface is used to reach the other location. For switches directly connected to the edge switch, use only routes from non-marked interfaces to marked interfaces and remove any routes from marked to marked or non-marked to non-marked interfaces. This operation for the directly connected switches allows single hops that are non-shortest path to an edge switch and removes certain potential loopback situations due to shortest path routes.