Duplicating RTP Streams
Cisco
University of Glasgow
Packet loss is undesirable for real-time multimedia sessions, but can occur due to congestion, or other unplanned network outages. This is especially true for IP multicast networks, where packet loss patterns can vary greatly between receivers. One technique that can be used to recover from packet loss without incurring unbounded delay for all the receivers is to duplicate the packets and send them in separate redundant streams. This document explains how Real-time Transport Protocol (RTP) streams can be duplicated without breaking RTP media streams, or RTP Control Protocol (RTCP) rules.