Subject: [AVT] Comment on draft-ietf-avt-srtp-ekt-00

From: Roni Even <[email-masked]>
Date: Tue, 11 May 2010 17:55:29 +0300

Hi, 

I read the draft and I saw that SRTP Encrypted Key Transport (EKT) is an
extension to SRTP that  provides for the secure transport of SRTP master
keys, Rollover  Counters, and other information, within SRTP or SRTCP.  This
facility  enables SRTP to work for decentralized conferences with minimal
control. In the document I saw some references to RTP mixers (with the
comment that they do not need EKT) and transport translator. 

I am not sure what is meant by decentralized conferences with minimal
control. I thought it can be a multicast conference or a video switching
conference or multipoint translator but could not find it in the text. I saw
the point to point offer answer use case.

I suggest that if the goal is to address the different multipoint scenarios
then the draft should reference RFC 5117 (topologies) and explain how EKT
works in these different topologies. 

I also think the it may be good to mention also SSM where there is a single
source multicast and a feedback target that receives unicast RTCP feedback
from the multicast receivers.

Roni Even

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