Processing mid-dialog SIP messages by receiving a mid-dialog SIP message from a SIP user agent client, creating a new SIP session, associating the new SIP session with the mid-dialog SIP message, identifying an application that is associated with the mid-dialog SIP message, providing to the application the mid-dialog SIP message in the context of the new SIP session, receiving an acknowledgement from the application that the application will accept the mid-dialog SIP message, and responsive to receiving the acknowledgement, providing to the application the mid-dialog SIP message in the context of the new SIP session.