Patent ID: 6944675
Filing Date: 2005-09-13
Classification: H04L

Abstract:
1. A router for a hierarchical communication network which is divided into a plurality of areas in each of which a plurality of said router are interconnected by links, comprising: a first table having a plurality of entries respectively corresponding to reachable destinations, each of the entries including one of an intra-area indication and an inter-area indication and an area identifier identifying at least one traversable area, wherein an intra-area destination is associated with only one area identifier; at least one second table corresponding to said at least one traversable area, each of said at least one second table holding quality-of-service (QoS) values of only the links of the corresponding at least one traversable area; and a processor, responsive to a request signal specifying a destination and a QoS value, for making reference to one of the entries of the first table and said at least one second table corresponding to the specified destination, selecting links of the area identified by the area identifier of the referenced entry which links satisfy the specified QoS value, and performing a calculation according to a shortest path finding algorithm on the selected links to find a shortest path to the specified destination if the intra-area indication is included in the referenced entry, or performing said shortest path calculation on the selected links to find a shortest path tree in the identified area if the inter-area indication is included in the referenced entry and determining a route from the shortest path tree.