Quality of signaling (QoSg) metrics for evaluating SIP transaction performance

Service quality and user-perceived experience has been a networking research topic for many years. Whereas most related work concentrates on the quality of media, only very few papers, however, discuss the performance of the signaling for those media. This paper addresses the performance of the Session Initiation Protocol (SIP) which is very popular with Next Generation Networks (NGN). A collection of metrics, the so-called Quality of Signalling (QoSg), is introduced for measuring SIP signaling delays. In contrast to traditional end-to-end performance metrics, QoSg aims at evaluating individual SIP transactions. Therefore, this approach can be applied anywhere in the SIP network and allows for additional insight, for instance regarding congestion detection or SLA monitoring.