Design for controlling media privacy in SIP conferencing systems

We propose a new focus of research for multimedia conferencing systems which allows each user to flexibly select another participant or a group of participants to control media transmission. In a traditional conference system, participants' voices might by default be shared with all others, but a participant might want to select a subset of the conference members to send his/her media to or receive streams from. We review the concept of narrowcasting, a technique for limiting such information streams in a multimedia conference, and propose a design to use existing standard protocols (SIP and SDP) for controlling fine-grained narrowcasting sessions.