Patent ID: 6424624
Filing Date: 2002-07-23
Classification: H04L

Abstract:
Method for performing congestion detection and flow control operations over data traffics including both discardable traffic and non-discardable traffic, in a high speed digital packet switching network including access and transit nodes interconnected by links or trunks, and wherein for any source end-user attached to said network via an entry access node and requesting its traffic to be vehiculated toward a destination end-user also attached to said network via an exit access node, a connection is established which includes so-called in-going (or forward) and returning (or backward) paths set from said entry node to said exit node and in the opposite direction from said exit node to said entry node respectively, which paths might include network transit nodes, said method including:monitoring the data flow in each transit node over the forward path from said entry node to said exit node for detecting traffic flow congestion in said monitored transit node and in case of flow congestion being detected therein, setting so-called Congestion Indication (CI) bit in a first predefined so-called header field of data packets on the involved forward path down to the exit node; said method being further characterized in that it includes: monitoring the incoming data packets entering said exit node, and in case of a set CI indication being detected therein, feeding this indication back to said entry node by setting a Return Congestion Indication (RCI) bit in a second predefined header field in the data packets of the traffic of said backward path; monitoring the packets received in said entry node over said returning (backward) path and integrating, in said entry node, said RCI bits indications over a predefined period of time, said integration meaning adding or subtracting one unit depending whether said RCI bit is detected to be at binary value one or zero, respectively, said integration producing an integrated RCI indication; monitoring said predefined time period, and when said time period is over, checking said integrated RCI indication; and, adjusting the communication bandwidth assigned to said discardable traffic over said forward path, from said entry node to said exit node in a predefined manner, according to said integrated RCI indications.