Patent ID: 6778535
Filing Date: 2004-08-17
Classification: H04L,H04Q

Abstract:
A method for providing Class-of-Service (COS) routing of a call or connection request between an origin node and a destination node in a multi-link network employing a Private Network-to-Network Interface (PNNI) protocol, comprising the steps of:(a) searching for a shortest path between the origin and destination nodes; (b) determining the class of service of the call; (c) determining for each link in the path whether said each link has available bandwidth for the Class of Service for the call by: (1) determining the sum of bandwidth required for each virtual channel setup for calls on their first choice path (BWPC); (2) determining the sum of bandwidth required for each blocked virtual channel setup (BWOV); (3) computing the link blocking level (LBL) as BWOV/BWPC; (4) establishing bandwidth reservation thresholds (Rthr) in accordance with the link blocking level; (5) determining the load state of the link in accordance with the established bandwidth reservation thresholds; and (6) establishing the availability of the link in accordance with the class of service of the connection request, the load state of the link, and a required bandwidth for the connection request class of service and if said each link in the shortest bath has sufficient available bandwidth, then routing the call to the destination node across the shortest path, otherwise, (d) if insufficient bandwidth is available on any of the links, then sending a crankback message to the origin node; thereafter searching for a next shortest path and then repeating step (c)(1)-(6).