Model-based verification of the SIP invite scenario

The Session Initiation Protocol (SIP) is a signaling protocol for multimedia control over the Internet. It is used for initiating, maintaining and terminating multimedia sessions. In this paper we have carried out the verification of the SIP Invite scenario with Coloured Petri nets (CP-nets or CPNs). First, we have specified and verified the protocol model using a simulation tool. Then, we have verified the scenario using a state space analysis tool. We have concluded that the SIP Invite transaction is free of livelocks, and has only desirable deadlocks. Therefore, no additional remodeling for the protocol Invite transaction is needed.