Closed conference signalling using the session initiation protocol

In a closed conference the identity of all conference participants is known by others and all participants are notified when a new user joins the conference. The Session Initiation Protocol (SIP) supports signalling of several conference models, but not of closed conferences. Introduces an extension of SIP for closed multiparty conferences. The extension expands SIP for the functionality for discovery of participant identities in a conference. Furthermore, it ensures that each conference participant is notified before a new participant joins. Verifies this extension by applying it to two SIP conference models – conference with conference server and full‐mesh conference. Ends with an analysis of additional signalling traffic that this extension generates.