Last Call Review of draft-ietf-avtcore-multi-media-rtp-session-11
review-ietf-avtcore-multi-media-rtp-session-11-secdir-lc-huitema-2015-12-10-00

I reviewed this document as part of the Security Directorate's ongoing
effort to review all IETF documents being processed by the IESG.  These
comments were written primarily for the benefit of the Security Area
Directors.  Document authors, document editors, and WG chairs should
treat these comments just like any other IETF Last Call comments.

Version reviewed: draft-ietf-avtcore-multi-media-rtp-session-10

Summary: Ready

The draft proposes to allow RTP streams to carry multiple media streams, 
relaxing the opposite requirement expressed in RFC 3550 and RFC 3551. 
The draft is well written and easy to understand, from the motivation of 
easier session establishment to the various details of RTP that have 
to be taken care of.

The security session addresses the main security implication of carrying
multiple media in a single stream. Whereas previous each media could be
secured independently, all media multiplexed on a single stream will share 
the same security protections. This can be positive if the security of all
meets the most stringent requirement, or negative if the implementers
picked a lowest common denominator. I don't believe that there is much 
of a practical concern there.

Note: I mistakenly sent previously a review for 
draft-westerlund-avtcore-multi-media-rtp-session-11, the version of
this draft before WG adoption. The final version contains many improvements,

but the security considerations are unchanged.

-- Christian Huitema