A Comparative Study on Load Balancing Algorithms for SIP Servers

The widespread acceptance and usage of smartphones deployed with high end operating systems have made Voice over IP applications extremely popular and prevalent globally. A large set of users amongst these use a plethora of Internet based applications after configuring them on their devices. SIP Proxy servers are predominantly used in these VOIP networks for the routing challenges arising from the requirement of supporting millions of VOIP concurrent/subsequent calls and also increasing the QoS (Quality of Service) of the routed calls. For intelligent load balancing, call dispatchers are used to achieve high throughput and minimum response times by balancing the calls amongst SIP proxy servers. Several load balancing algorithms are used like round robin, Call-Join-Shortest-Queue (CJSQ), Transaction-Join-Shortest-Queue (TJSQ) and Transaction-Least-Work-Left (TLWL). In this paper, we present a comparative analysis of load balancing algorithms for SIP servers with respect to call response time and server throughput performance.