Subject: [Perc] Genart telechat review of draft-ietf-perc-srtp-ekt-diet-11

From: Christer Holmberg via Datatracker <[email-masked]>
Date: Fri, 31 Jan 2020 03:48:17 -0800

Reviewer: Christer Holmberg
Review result: Ready with Issues

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Document: draft-ietf-perc-srtp-ekt-diet-11
Reviewer: Christer Holmberg
Review Date: 2020-01-31
IETF LC End Date: None
IESG Telechat date: 2020-02-06

Summary:

I took a long time before I got a reply to my original review comments, and now
I realize that I never addressed that reply. Sorry for that.

In my previous review, I had a number of editorial suggestions (Minor Issues),
and in many cases the author did not agree to those. I will not pursue those,
but leave it to the IESG to decide whether something needs to be done.

Many of my issues have been addressed in the latest version. However, I do
still have a couple of issues. One of them (Q1_1) is a follow-up from my
previous review, and for convenience I will include the discussion content in
this review.

Major issues:

Q1_1:

>> The text in section 1 says that EKT removes the need for coordinating
>> SSRCs,and that an endpoint can choose whatever value it wants.
>>
>> However, I can't find any explanation on how EKT removes that need.
>
> The answer is toward the end of the introduction: "EKT does not control the
> manner in which the SSRC is generated..." -- it just makes the distribution
> of security information easier.  I extended that paragraph to clarify.

As far as I understand, SSRC collisions can still occur. But, if that occurs,
endpoints can provide the new SSRC using EKT – without the need for OOB
solutions or signaling – and that is the reason EKT removes the need for
coordinating SSRCs. I think it would be good to clarify that.

Q_1_2:

Section 5.3 reference RFC 3264 for the Offer/Answer procedures. However, since
the text is specific to DTLS-SRTP, I think the reference should be to RFC 5763
and draft-ietf-mmusic-dtls-sdp.

I assume this also applies to the RFC 3264 reference in Section 4.1
(SRTPMasterKeyLength definition).

Minor issues:

N/A

Nits/editorial comments:

N/A