A simulation study of multi-recipient messages in the session initiation protocol

In a multiparty session a signaling message is often sent to several or to all session participants. Nowadays. these messages are usually sent over unicast to each participant in turn. because there are serious security problems when a signaling message is sent over multicast. On the other side, replicated messages over unicast essentially increase signaling traffic when the number of message recipients increases. This paper introduces an extension to the Session Initiation Protocol (SIP) that reduces the signaling traffic for multirecipient messages. We also present the result of simulations where we compare the signaling traffic with and without the extension. Several simulation scenarios are presented and analyzed and all of them clearly show that the extension considerably reduces the signaling traffic for multi-recipient messages, even when some SIP components do not support the extension.