Abstract: A process for selecting a least weight path between two nodes in a data communication network uses partial trees created and cached in prior route selection operations. All root nodes on possible paths between the two nodes are identified. Any cached tree having a root matching one of the identified root nodes is retrieved from storage. If necessary, each retrieved tree is extended until it includes all possible destination nodes. The extended and/or retrieved trees are used to select the least weight path between the two nodes. The extended tree is then cached for possible use in future route selection operations.

Abstract: A least weight route computation algorithm for use in computing routes through a data communications network is improved by recording the number of equally weighted paths to a particular node through different predecessor nodes. If a route must be selected to the particular node, the relative numbers of equally weighted routes through different predecessor nodes determines the probability with which a route will be selected through the particular predecessor node.

Abstract: When computing a least weight path from an origin node to a destination node in a data communication network, a route-computing network node uses information provided by the origin and destination nodes to compute least weight routes from those nodes to adjacent network nodes. The route-computing network node uses information in the topology database to compute least weight routes from network nodes adjacent the origin node to network nodes adjacent the destination node. The results of the computations are concatenated to determine an optimum route from the origin node to the destination node. The topology database need not include information about the transmission groups connecting the origin/destination nodes to network nodes.