Re: [rtcweb] mdns-ice-candidates: Single IP address:port

[youenn fablet <[e-mail]>]

>
> Part of why this wasn't simple enough to slipstream into the existing
> documents is that we don't have well-defined handling in SDP for dealing
> with names in the <connection-address> field of "c=" lines. The extent of
> RFC 4566's text on the topic is:
>
>
>    A session description can contain domain names in the "o=", "u=",
>    "e=", "c=", and "a=" lines.  Any domain name used in SDP MUST comply
>    with [1], [2].  Internationalised domain names (IDNs) MUST be
>    represented using the ASCII Compatible Encoding (ACE) form defined in
>    [11] and MUST NOT be directly represented in UTF-8 or any other
>    encoding (this requirement is for compatibility with RFC 2327 and
>    other SDP-related standards, which predate the development of
>    internationalised domain names).
>
>
> Unfortunately, this doesn't provide a lot of clarity about what happens if
> a DNS lookup of the corresponding domain name returns multiple A or AAAA
> records. (The fact that "c=" lines clearly indicate their address family
> saves us from having to worry about any happy-eyeballs-style address family
> fiddling, but the handling of name lookups is still somewhat ambiguous).
>
> So I think we need to reach a common understanding about how to handle the
> normal name-to-address mapping case, and then apply the same principle to
> mDNS as we do to DNS.
>
I agree with the principle.
In practice though, MDNS might be simpler to use.
The MDNS specification does not require an application to register a name
for both IPv4 and IPv6.
We might end up with two different MDNS ids for IPv4 and IPv6, each id
resolving to exactly one record.