Quality of signalling: A new concept for evaluating the performance of non-INVITE SIP transactions

Providing Quality of Service (QoS) and Quality of Experience (QoE) in connection with media data like audio or video is of key importance for the evolution of future packet-based networks. Especially in telecommunications, the subjective service quality as perceived by the end user depends amongst other parameters on the setup success rate as well as on the delay for session setup, which is measured end to end. In this paper, we introduce the new concept of “Quality of Signaling” (QoSg) and present an analysis based on Session Initiation Protocol (SIP) networks, where messages traverse usually several hops (SIP proxies) and several connections. SIP introduces the concept of transactions that are managed hop-by-hop and form the basic building blocks for SIP signaling. We argue that the end-to-end service quality strongly depends on the performance of these transactions and provide a comprehensive analytic, simulative and measurement-based performance evaluation of single SIP transactions.