RTP: Audio and Video for the Internet

The use of RTP header compression ”whether CRTP or ROHC ”can significantly improve performance when RTP is operating over low-speed network links. When the payload is small ”say, low-rate audio, with packets several tens of octets in length ”the efficiency to be gained from CRTP with 2-octet compressed headers, compared to 40-octet uncompressed headers, is significant. The use of ROHC can achieve even greater gains in some environments, at the expense of additional complexity.

Header compression is beginning to be widely deployed. ROHC is an essential part of third-generation cellular telephony systems, which use RTP as their voice bearer channel. CRTP is widely implemented in routers and is beginning to be deployed in end hosts .