Last Call Review of draft-ietf-tsvwg-fecframe-ext-04
review-ietf-tsvwg-fecframe-ext-04-genart-lc-holmberg-2018-09-14-00

I am the assigned Gen-ART reviewer for this draft. The General Area
Review Team (Gen-ART) reviews all IETF documents being processed
by the IESG for the IETF Chair.  Please treat these comments just
like any other last call comments.

For more information, please see the FAQ at

<https://trac.ietf.org/trac/gen/wiki/GenArtfaq>.

Document: draft-ietf-tsvwg-fecframe-ext-04
Reviewer: Christer Holmberg
Review Date: 2018-09-14
IETF LC End Date: 2018-09-24
IESG Telechat date: Not scheduled for a telechat

Summary: The document is well written, but there is an issue regarding backward
compatibility that I want the authors to address.

Major issues:

Q1_MAJ:

Regarding backward compatibility, it's difficult for me to parse the second
bullet in Section 1.

The text seems to assume that SDP, and RFC 6364, are used to negotiate FEC.
But, RFC 6364 is only an informative reference, and I assume FEC does not even
mandate SDP?

Is there a generic requirement that the endpoints must negotiate the usage of
this mechanism before it is used? Or, can the mechanism be used towards an
endpoint that does not support it?

Minor issues:

N/A

Nits/editorial comments:

Q2_ED.

The document uses "extends RFC 6363" terminology in a couple of places. I
suggest to use "updates" instead.

Q3_ED.

Section 1 says:

     'This document is fully backward compatible with [RFC6363] that it extends
     but does not replace."

I don't think you need the "extends but does not replace" part.