Priority Queuing Strategy for Self-Overload Control in SIP Servers

The Session Initiation Protocol is an IP based application level signaling protocol. SIP uses various overload control techniques out of which self-overload control using queuing strategies is one. This research work identifies the problem arising due to retransmission of SIP requests and introduces an Advanced Smart Priority Queuing Strategy to increase the resiliency of SIP server. SIP request retransmissions are reduced by giving high priority for requests starving in queues for longer durations. The reduction in queuing delays and the stability condition are evaluated, for identifying the capacity of the SIP server, using analytical methods and validated the same using simulation method. This work compared the server recovery time when using FIFO Queuing Strategy and Smart Priority Queuing Strategy with proposed Advanced Smart Priority Queuing Strategy. With Advanced Smart Priority Queuing Strategy, the capacity of the SIP servers has been increased by 81.90% and server recovery time has been reduced by 83.63%.