US 6,982,956 B2 | ||
System and method for controlling communications network traffic through phased discard strategy selection | ||
Alain Blanc, Tourrettes sur Loup (France); and Francois LeMaut, Nice (France) | ||
Assigned to International Business Machines Corporation, Armonk, N.Y. (US) | ||
Filed on Apr. 25, 2001, as Appl. No. 9/843,315. | ||
Claims priority of application No. 00480035 (EP), filed on Apr. 26, 2000. | ||
Prior Publication US 2001/0036157 A1, Nov. 01, 2001 | ||
Int. Cl. H04L 12/56 (2006.01) |
U.S. Cl. 370—235 | 6 Claims |
1. A method for controlling congestion at an output from a node in a data communications network wherein data is transmitted
in packets, each packet having a discardability characteristic, said method comprising the steps of:
establishing a set of available, alternative discard strategies for packets having different discardability characteristics;
maintaining a profile of packets recently received at the output, the profile reflecting the discardability characteristics
of said packets, wherein the step of maintaining a profile further comprises the steps of maintaining a count of the number
of packets actually stored in an output buffer at the output, and maintaining counts of the number of said packets which would
have been stored in the output buffer if different discard strategies in a set of available discard strategies had been in
effect during the receipt of the packets actually stored in the output buffer,
monitoring the output to detect the onset of congestion;
upon detection of congestion, using the profile to select an initial discard strategy;
initiating the selected initial discard strategy;
continuing to monitor the degree of congestion at the output; and
selecting and initiating one or more subsequent discard strategies as the degree of congestion changes, wherein each successively
initiated discard strategy is intended to result in the discard of fewer packets than the previously initiated discard strategy.
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