SIP overload control

Overload happens in Session Initiation Protocol (SIP) networks when SIP servers have insufficient resources to handle all messages they receive. Under overload, SIP networks suffer from congestion collapse due to its ineffective overload control mechanism. In this paper we propose a backpressure-based SIP overload control mechanism called Bassoon. It consists of two parts: the first part is a provably optimal load balancing algorithm that ensures full utilization of the available network resources. The second part is an end-to-end load control algorithm that intelligently throttles excessive traffic at the edge of the network. We show that, by combining optimal load balancing and end-to-end load control, Bassoon effectively controls overload in SIP networks and outperforms existing schemes in terms of goodput, fairness and responsiveness.