Novel overload controls for SIP networks

The increasing use of SIP in next generation networks necessitates that SIP networks provide adequate control mechanisms to optimize transaction throughput and prevent congestion collapse during traffic overloads. SIP elements need well behaved internal overload controls to detect and throttle traffic, and external controls between SIP elements are needed to throttle traffic closer to the source. This paper presents the results of simulations that demonstrate the inadequacy of current SIP controls, and then presents several novel algorithms to control SIP network overloads. We show our new algorithms increase goodput across increasing load levels, are robust to IP loss and delay, and perform well under transient burst loads.