International Business Machines Corporation

Gary John DeVal

Curtis E Hrischuk

Charles P Wright

Erich Miles Nahum

John Michael Tracey

Mark A Johnson

Craig Andrew Lanzen

Xiping Wang

Brian L Pulito

James Winston Lawwill, Jr

Timothy Paul Pickett

Michael S Fulton

Ryan Andrew Sciampacone

A technique for use in a client, wherein the client supports a state-based signaling protocol (e.g., Session Initiation Protocol or SIP), includes initiating a given session state between the client and a server that also supports the state-based signaling protocol, and refreshing the given session state in a randomized manner. Further, a technique for use in a server, wherein the server supports a state-based signaling protocol (again, e.g., SIP), includes randomly assigning an expiration time duration for a given session state between the server and a client that also supports the state-based signaling protocol, and reporting the randomly assigned expiration time for the given session state to the client. By randomizing various behaviors of the client, the server, or both, bursty traffic in the communication network is reduced or eliminated.

Methods and apparatus for randomization of periodic behavior in communication network

The number of CPU cycles required to reclaim object memory space in a memory management process is reduced by using a two phase approach. A data structure exists for each object that is to be loaded into object memory space. One part of the data structure is the object definition. The other part is a MM (Memory Management) immunity annotation or value that controls the frequency with which the object must actually be examined to determine if it is suitable for reclamation. On each iteration of the memory management process, the object's MM immunity value is tested to determine whether it is greater than a predetermined threshold. If greater than the threshold, the value is decremented, but the object is not actually examined for its suitability for removal. If the value equals the threshold, the object itself is examined. If it is found to be suitable, it is removed to reclaim the object memory space it previously occupied, If it is actually examined but is found not to be suitable for removal, the MM immunity value is reset to its original value or is otherwise adjusted to prevent examination of the object for a certain number of future iterations of the memory management process.

Computer system memory management

The present invention manages the execution of multiple AMM cycles to reduce or eliminate any overlap. Specifically, the present invention provides an external supervisory process to monitor the AMM behavior of VMs on one or more nodes, and intervene when coincident AMM activity appears to be imminent. If AMM patterns suggest that two VMs are likely to perform a (e.g., a major) AMM cycle simultaneously (or with significant overlap) in the near future, the supervisory process can trigger one of the VMs to AMM immediately, or at the first 'safe' interval prior to the predicted AMM collision. This will have the effect of desynchronizing the AMM behavior of the VMs and maintaining AMM latency for both VMs within the expected bounds for their independent operation, without any inter-VM effects.

Automatic memory management (AMM)

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.

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Raleigh, NC, United States of America

Gary John DeVal