Re: [MMUSIC] FQDN Support Final Vote

[Roman Shpount <[e-mail]>]

On Tue, May 21, 2019 at 5:09 PM Christer Holmberg <
[e-mail]> wrote:

> >4. Clarify ICE support validation procedures when processing session
> descriptions with FQDN in candidate connection address. Specifically, if
> agent implementing ice-sip-sdp receives a session >description where
> candidate with FQDN connection address is the default candidate, address in
> c= line must be the literal FQDN value used connection address of the
> default candidate. If >address in c= line is an IP address which is result
> of the FQDN resolution of candidate connection address, or FQDN which
> resolves to the same IP address as FQDN in the candidate, or anything >else
> except the literal FQDN value used in the default candidate connection
> address, then this m= line must be treated as ICE mismatch. On the other
> hand, difference in address family and type >between c= line and FQDN
> resolution result (regardless of what procedure is used to resolve FQDN),
> must not be considered a mismatch.
>
>
>
> It is very difficult for me to parse what you are trying to say in bullet
> 4.
>
>
>
> If an agent receives SDP with an IP address in the c= line, how does it
> know whether it is a “result of the FQDN resolution of the candidate
> connection address”? Does that agent have to do a DNS lookup after all, to
> see whether the result matches the IP address in the c= line?
>

I am talking about Verifying ICE Support Procedures (
https://tools.ietf.org/html/draft-ietf-mmusic-ice-sip-sdp-27#section-3.2.5)
when session description is received with FQDN in default candidate. What I
am saying is that when validating ICE Support, connection address in c=
line MUST be literal FQDN from default candidate. Not its IP address or
some other resolution result, but actual FQDN. Also, in case FQDN is used
in default candidate, ice mismatch should not be caused by any values of
address family and type in c= line. This way client does not need to do
FQDN resolution when validating ICE support. For instance, Suhas suggests
that IP address and family should be used in c= line when FQDN is used in
default candidate, but, in this case, ICE support cannot be validated
without resolving FQDN and even this can produce accidental ICE mismatch
based on resolution result.

> I do not like the current language in ice-sip-sdp, since it does provide
> a description on how connection addresses with FQDN are generated and
> handled, but does it in a way that is known to
>
> > cause problems. Also, current language does not allow for FQDN to be
> ignored or specify how ICE mismatch conditions are handled when FQDN
> connection address is used.
>
>
>
> I don’t think anyone disagree with changing the current text?
>

Suhas is arguing for existing text.

Regards,
_____________
Roman Shpount