Flow Management for SIP Application Servers

Building healthy, long-running SIP application servers is more challenging than WEB servers. Since SIP has been adopted by telecom industry, SIP servers should meet carrier-grade QoS requirement, which is more critical than WEB services. SIP messages are well organized into sessions. When a server experiences an incoming message burst or a relatively long time of overload, many transactions would experience very long response time, even resulting in session failures. This is not acceptable by telecom providers. Unlike http, most SIP messages are transmitted by UDP protocol and retransmissions are employed to improve the transmission reliability. However, these retransmissions would exacerbate the situation when the server is under high load. In this paper, we use front-end flow management to address these challenges simultaneously. Our method integrates concurrency limit, message scheduling, and admission control to achieve overload protection and QoS guarantee. We also devise some novel techniques such as twin-queue scheduling, retransmission removal, and GC detection to improve the effectiveness of the method. Experiments show that the system apparently reduces the average response time and improves the response time distribution.

By: Jing Sun; Jinfeng Hu; Ruixiong Tian; Bo Yang

Published in: RC24053 in 2006


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