Patent ID: 8175241

Claim:
A system for adding participants to an ongoing conference call, comprising: a handset configured to send a single Session Initiation Protocol (SIP) REFER message containing a list of a plurality of prospective participants to be added to the ongoing conference call, the list of prospective participants comprising a group of prospective participants created prior to the time of the conference call and an ad hoc list of individual participants created substantially contemporaneously with the conference call, the group identified by a group identifier, the single SIP REFER message comprising first and second Content-Disposition sections, the first Content-Disposition section including separate entries for each of the individual participants in the ad hoc list and the second Content-Disposition section including an entry for the group identifier identifying the group; and an application server configured to receive the message and invite the prospective participants, the application server further configured, in response to receiving an acknowledgement from the prospective participants to participate in the ongoing conference call, to add the prospective participants in the conference call, the application server further configured, upon a determination that one of the prospective participants is a member of a different network than an organizer of the conference call, to send an invitation to the different network.