Re: [rtcweb] [MMUSIC] What goes into c= line address when FQDN is used for the default candidate?

Lorenzo Miniero <lorenzo@meetecho.com> Thu, 07 February 2019 16:58 UTC

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Date: Thu, 7 Feb 2019 17:58:07 +0100
From: Lorenzo Miniero <lorenzo@meetecho.com>
To: Justin Uberti <juberti=40google.com@dmarc.ietf.org>
Cc: Harald Alvestrand <harald@alvestrand.no>, RTCWeb IETF <rtcweb@ietf.org>
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Subject: Re: [rtcweb] [MMUSIC] What goes into c= line address when FQDN is used for the default candidate?
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On Thu, 7 Feb 2019 08:28:06 -0800
Justin Uberti <juberti=40google.com@dmarc.ietf.org> wrote:

> Note also that only host candidates will be mDNS; srflx and relay
> candidates will continue to work as before.
> 


I assume you mean host candidates associated with *private* addresses,
and not host candidates associated with public addresses as well? In the
latter case, not sure what benefit mDNS would be supposed to provide,
if it can be used at all.

Lorenzo


> 
> 
> On Thu, Feb 7, 2019 at 8:01 AM Harald Alvestrand
> <harald@alvestrand.no> wrote:
> 
> > Den 05.02.2019 16:03, skrev Alan Ford:  
> > > If that update was to be made, this goes against the text
> > > in draft-ietf-rtcweb-mdns-ice-candidates-02 which says:
> > >
> > >    An ICE agent that supports mDNS candidates MUST support the
> > > situation where the hostname resolution results in more than one
> > > IP address. In this case, the ICE agent MUST take exactly one of
> > > the resolved IP addresses and ignore the others.  The ICE agent
> > > SHOULD, if available, use the first IPv6 address resolved,
> > > otherwise the first IPv4 address.
> > >
> > > But there’s a bigger problem here, which is how to cope with an
> > > FQDN is not resolvable. So the intention, as I understand it, is
> > > that when these host candidates leave the mDNS domain and are
> > > thus not resolvable, they will be treated as peer reflexive
> > > candidates.
> > >
> > > But at that point there is no address family information
> > > available, so how does an ICE agent know to do pairing with these
> > > candidates, which requires the address family to be known?  
> >
> > Peer reflective candidates are identified by means of an incoming
> > packet. The address family is very obvious from the packet.
> >
> > _______________________________________________
> > rtcweb mailing list
> > rtcweb@ietf.org
> > https://www.ietf.org/mailman/listinfo/rtcweb
> >  



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