The draft SIP Multiple REFER describes a way to send a call transfer (REFER) indicating setup of a new call to multiple destinations, i.e. initiating a conference. This could be handy between two Asterisk servers, a way to set up a conference on a different server, optimized for conferences.

RFC 3261 (SIP) [RFC3261] is extended by RFC 3515 [RFC3515] with aREFER method that allows a user agent to request a server to send a request to a third party. Still, a number of applications need torequest a server to initiate transactions towards a set of destinations. In one example, the moderator of a conference may wantthe conference server to send BYE requests to a group of participants. In another example, the same moderator may want the conference server to INVITE a set of new participants. We define an extension to the REFER method so that REFER request can be used to refer servers to multiple destinations. In addition, this mechanism uses the suppression of the REFER method implicit subscription specified in RFC 4488 to suppress REFER’s implicit subscription.