Technical Summary
This specification defines an integrity transform for SRTP so the
roll-over counter (RoC) can be carried in SRTP packets as part of the
authentication tag. This allows late-joining receivers to easily
synchronize with the sender. Other mechanisms include estimating the
RoC, which is not as robust as actually carrying the RoC in the
packets. The RoC is carried in every rth packet, which is bandwidth-
sensitive.
Other alternative solutions might be to use RTCP for RoC
synchronization. At the moment, 3GPP, 3GPP2 and other broadcast
systems do not specify the use of RTCP and hence the RTP-based
solution specified in this document is more useful.
Working Group Summary
This is not a WG document. The notion of additional data transport in
RTP was discussed on RTPsec mail list.
Protocol Quality
Once this is published, OMA BCAST and 3GPP MBMS compliant systems may
use this feature.
This document was reviewed by Russ Housley for the IESG.