[MMUSIC] ietf-mmusic-mdns-ice-candidates-01 Nils review

[Nils Ohlmeier <[e-mail]>]

Hello,

I was asked to review https://datatracker.ietf.org/doc/html/draft-ietf-mmusic-mdns-ice-candidates-01

Here are my comment and questions:

Abstract:
“To maximize the probability of a
   direct peer-to-peer connection, client private IP addresses are
   included in this candidate collection.”

I think it would make sense to replace “client” with ICE agent here, as client and server in the pure ICE context doesn’t make too much sense. I would suggest to change it to “..., private IP addresses of the ICE agent are included…”.

In the abstract the terms “private IP addresses” and “local IP addresses” are used. I would suggest sticking to just one term for consistency. Section 1. “Introduction” has the same mix of local vs private in it.

Section 3.1.1 point 1
I think it would be helpful if this draft at least offers the suggestion to replace all RFC1918 addresses, or put a reference to section 3.1.2.2 as a recommendation on how to determine which addresses to replace.

Section 3.1.2.2 3rd paragraph
“Regardless of results, …” confuses me. The last sentence in the paragraph before talks about the case of a public candidate. If I’m not mistaken in the case of a public address there shouldn’t be a server reflexive candidate generated.

Section 3.1.2.2 4th paragraph
While I agree that caching the result might be useful it can become dangerous in case the set of STUN servers changes. As the new STUN servers might return different results, cached results should be invalidated. Would it be worth adding a warning about this?

Section 6.4
I’m confused by the diagram showing that both agents send over their mDNS candidates before having checked with the STUN server if the interface IP addresses need to be filtered or not. I understand that section 3.1.2.2 recommends to first wait for the STUN binding response from the STUN server before deciding which addresses should be filtered and which not. Why is this example showing it differently?

Best regards
  Nils Ohlmeier