Integrity Transform Carrying Roll-Over Counter for the Secure Real-time Transport Protocol (SRTP)
RFC 4771

Approval announcement
Draft of message to be sent after approval:

From: The IESG <iesg-secretary@ietf.org>
To: IETF-Announce <ietf-announce@ietf.org>
Cc: Internet Architecture Board <iab@iab.org>,
    RFC Editor <rfc-editor@rfc-editor.org>
Subject: Protocol Action: 'Integrity Transform Carrying 
         Roll-over Counter' to Proposed Standard 

The IESG has approved the following document:

- 'Integrity Transform Carrying Roll-over Counter '
   <draft-lehtovirta-srtp-rcc-07.txt> as a Proposed Standard

This document has been reviewed in the IETF but is not the product of an
IETF Working Group. 

The IESG contact person is Russ Housley.

A URL of this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-lehtovirta-srtp-rcc-07.txt

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.