Local and distributed SIP overload control solution improving sustainability of SIP networks

Summary Carriers have adopted session initiation protocol (SIP) in their next generation networks. Providing carrier-grade service requires high availability in times of component failures, avalanche restart, flash crowds and denial of service attacks, which cause overload on SIP servers. Throughput of SIP servers is largely degraded during overload. We propose an SIP overload control (SIP-OC) solution for local and remote situations, working in hop-by-hop and end-to-end modes. Our local SIP-OC method uses a cross-layer approach with negligible performance impact, while the implicit nature of our remote SIP-OC allows detection of sophisticated overload conditions such as those caused by non-SIP entities. Our remote SIP-OC uses transaction response time as the basis for implicit overload detection. Coupling our local and remote SIP-OC schemes, we show that the range of ‘sustainable’ overload that can be imposed on the system improves significantly. Moreover, incorporating a 2-means filtering mechanism into our SIP-OC scheme makes it perform well under packet-loss. We also show that our proposed solution is robust to network latency and SIP server capacity fluctuations. All of our results are obtained from experiments over SIP testbeds including an experimental IP multimedia subsystem. Copyright © 2016 John Wiley & Sons, Ltd.