Improving authentication performance of distributed SIP proxies

Abstract

The performance of SIP proxies is critical for the robust operation of many applications. However, the use of even light-weight authentication schemes can significantly degrade throughput in these systems. In particular, systems in which multiple proxies share a remote authentication database can experience reduced performance due to latency. In this paper, we investigate how the application of parallel execution and batching can be used to maximize throughput while carefully balancing demands for bandwidth and call failure rates. Through the use of a modified version of OpenSER, a high-performance SIP proxy, we demonstrate that the traditional recommendation of simply launching a large number of parallel processes not only incurs substantial overhead and increases dropped calls, but can actually decrease call throughput. An alternative technique that we implement, request batching, fails to achieve similarly high proxy throughput. Through a carefully selected mix of batching and parallelization, we reduce the bandwidth required to maximize authenticated signaling throughput by the proxy by more than 75%. This mix also keeps the call loss rates below 1% at peak performance. Through this, we significantly reduce the cost and increase the throughput of authentication for large-scale networks supporting SIP applications.

A Comparative Study of SIP Overload Control Algorithms

“…As a default part of numerous operating systems, SIP Express Router (SER) provides a load balancing module to mitigate the overload caused by large subscriber populations or abnormal operational conditions (IP Telecommunications Portal, 2011). Dacosta, Balasubramaniyan, Ahamad, & Traynor (2009) analyzed the relationship between the latency of message delivery and call throughput in a network configuration where SIP proxies are distributed but the database servers are centralized. Request batching was combined with parallel execution to balance the demands for bandwidth and the call failure rates of a SIP proxy, thus improving call throughput and reduce call failure rate significantly (Dacosta, Balasubramaniyan, Ahamad, & Traynor, 2009).…”

“…Dacosta, Balasubramaniyan, Ahamad, & Traynor (2009) analyzed the relationship between the latency of message delivery and call throughput in a network configuration where SIP proxies are distributed but the database servers are centralized. Request batching was combined with parallel execution to balance the demands for bandwidth and the call failure rates of a SIP proxy, thus improving call throughput and reduce call failure rate significantly (Dacosta, Balasubramaniyan, Ahamad, & Traynor, 2009). Jiang et al (2009) proposed three novel algorithms for balancing load across cluster-based SIP servers.…”