Method of caching routes in asynchronous transfer mode PNNI networks

In a network based on the Private Network to Network Interface (PNNI) standard and consisting of a plurality of nodes, a method of caching routes generated using the Dijkstra algorithm into a plurality of caches maintained on each node, each cache supporting a different class of call, said Dijkstra algorithm utilizing a PATH list in the calculation of routes, said method comprising the steps of:

• maintaining N sets of variables consisting of a cache sequence number, a parent pointer and a global cache sequence count for each node wherein each set of variables is associated with a single class of call to be supported;
• setting said cache sequence number, within a particular set of variables corresponding to a particular class of call, equal to said cache sequence count when the node is placed onto said PATH list;
• and
• constructing a routing list directly from parent pointers, defining a route from a destination node to a local node, if said cache sequence number, within a particular set of variables corresponding to a particular class of call, equals said cache sequence count within the set of variables thereof.