Subject: [AVTCORE] Open issues with draft-ietf-avtcore-ecn-for-rtp-05.txt

From: Colin Perkins <[email-masked]>
Date: Mon, 28 Nov 2011 16:28:47 +0000

AVTCORE working group,

Following on from the presentation in AVTCORE at IETF 82, there are two remaining open issues with the ECN-for-RTP draft:

1) Interactions with ICE: Dan Wing noted that the rules for checking that a path is ECN capable using STUN/ICE can add additional call setup time, and proposed that the draft be modified to allow STUN check for ECN validation to be done in parallel with the media. The authors agree with this, and are working with Dan to draft appropriate text.

2) Support for Multicast: Bill Ver Steeg noted that the draft needs all receivers, and the paths to all receivers, of a multicast flow to support ECN, else it falls back to not using ECN. This is very conservative, and does not scale to large groups. The authors agree with the concern, but don't currently have an alternative that doesn't cause serious fairness problems. We propose to add a note to say that the multicast ECN rules are known to be conservative, and may be relaxed in a future version of the specification; and to encourage experimentation to determine a less conservative, but still relatively fair, response.

If there are comments or objections to these proposals, please raise them on the list. We expect to submit a revised draft before the Christmas holiday.

Colin

-- 
Colin Perkins
http://csperkins.org/