An extensible RTCP control framework for large multimedia distributions

Abstract

The Real-time Transport Control Protocol (RTCP) is a crucial mechanism used, amongst other things, for synchronisation and feedback control in multimedia sessions. However as groups grow to large numbers, it faces two serious challenges: the growing deployment of unidirectional and asymmetric broadcast architectures, such as Source-Specific Multicast and satellite networks, eliminate the shared control backchannel on which RTCP relies; the per-receiver RTCP reporting frequency diminishes prohibitively due to the bandwidth-sharing algorithm. We present new algorithmic techniques that enable RTCP to combat these issues, allowing it to function in a wider range of environments and to scale to larger groups.