International Business Machines Corporation

Timothy Paul Pickett

Curtis E Hrischuk

Mark A Johnson

Craig Andrew Lanzen

Brian L Pulito

James Winston Lawwill, Jr

Gary John DeVal

A method, system and computer program product for limiting extreme loads and reducing fluctuations in load at session servers. An admission rate controller of a SIP router calculates the 'deflator ratio' equal to the average number of in-dialog messages received over a first fixed interval of time divided by the average number of out-of-dialog messages received over a second fixed interval of time. Further, the admission rate controller calculates the 'dampening ratio' equal to the maximum number of messages allowed over a period of time divided by the number of messages admitted over a previous time interval. When an overload condition has been detected, the admission rate controller calculates the maximum number of out-of-dialog messages to be sent to its associated SIP server based on the deflator and dampening ratios. In this manner, a smoother transition from the overload condition to the non-overload condition may occur.

Limiting extreme loads at session servers

A method, system and computer program product for managing bursts of traffic. A counter, referred to herein as a 'frequency counter,' is incremented during those time intervals an overload condition is detected and is decremented during those time intervals an overload condition is not detected. An overload condition may refer to when the number of out-of-dialog messages exceeds a threshold value corresponding to the maximum number of out-of-dialog messages that should be accepted and forwarded to an associated session server. If the count of the frequency counter exceeds some pre-configured value, then traffic that exceeds the threshold for the overload condition is stopped from being sent to the associated session server. Otherwise, traffic that exceeds the threshold for the overload condition is permitted to be sent to the associated session server. By managing bursts of traffic in such a manner, the effective utilization of session servers is improved.

Managing bursts of traffic in such a manner as to improve the effective utilization of session servers

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Rochester, MN, United States of America

Timothy Paul Pickett