Performance management of Java-based SIP application servers

Within the activities of the Java APIs for Integrated Networks (JAIN), the Java community offers a set of standard frameworks and open protocol APIs to create advanced telecommunications services. However, recent works have pointed out that Java-based implementations of the Session Initiation Protocol (SIP) stack, the fundamental signalling protocol in the convergent telephone-IP world, perform poorly if they are executed by large multi-core servers, typically used in data centres. The problem lies in the combination of the SIP protocol semantics with the Java language features, which does not allow fully exploiting the computing capabilities of multi-core architectures. To face this problem, we propose a solution to improve the throughput and signalling latency of applications implemented by using Java-based SIP application servers. It consists of the joint usage of virtualization and parallelization techniques. We have performed an extensive measurement campaign by using an open source application server compliant with the JSLEE (JAIN Service Logic Execution Environment) specifications. The rationale of this choice is that JSLEE application servers are currently regarded as very promising candidates for deploying telecom services. Results show that it is possible improving performance in terms of throughput and signalling latency by running more instances of the JSLEE server in parallel, each of them into separate virtual machines deployed on the same server. This improvement can increase throughput values of about 64% and, in the maximum throughput condition, the call set up latency can be nearly halved.