W3C home > Mailing lists > Public > public-webrtc@w3.org > June 2013

Re: Allowing RTCIceServer to contain multiple URLs

From: Eric Rescorla <ekr@rtfm.com>
Date: Fri, 7 Jun 2013 09:44:16 -0700
Message-ID: <CABcZeBMYYrY1PmO0BVUbVm4LxDCdg+fPqjtnuuLVu8=gLGwocg@mail.gmail.com>
To: "Cullen Jennings (fluffy)" <fluffy@cisco.com>
Cc: Justin Uberti <juberti@google.com>, Martin Thomson <martin.thomson@gmail.com>, "public-webrtc@w3.org" <public-webrtc@w3.org>
On Fri, Jun 7, 2013 at 4:11 AM, Cullen Jennings (fluffy)
<fluffy@cisco.com>wrote:

>
> On Jun 7, 2013, at 11:55 AM, Eric Rescorla <ekr@rtfm.com>
>  wrote:
>
> >
> >
> >
> > On Thu, Jun 6, 2013 at 9:42 PM, Cullen Jennings (fluffy) <
> fluffy@cisco.com> wrote:
> >
> > On Jun 6, 2013, at 10:30 PM, Justin Uberti <juberti@google.com> wrote:
> >
> > > The sections you are pointing to discuss the use of SRV to perform a
> lookup of a STUN or TURN server for a particular domain. How did you see
> this working with a TURN URI?
> > >
> > > That is, if the TURN URI specifies turn:foo.example.com, are you
> expecting the browser to do a SRV lookup of _turn._udp.foo.example.com,
> _turn._tcp.foo.example.com, and _turns._tcp.foo.example.com - each of
> which will return a DNS name that will require another query to obtain the
> IP address?
> > >
> > >
> >
> > Yes. Pretty much. Keep in mind the server has no idea which will works
> so you are going to need to try the transports to see what works.
> >
> > A TURN client could lookup the UDP, start trying that  and in parallel
> go get DNS for tcp and test the TCP. If UPD (or TCP) does not work, it
> takes awhile to detect so parallel works out better.
> >
> > Do we have measurements on the SRV success rate from typical browser
> clients?
>
> Any reason to think it might be less than say A records?


Yes. The Web doesn't work without A records but it works just fine w/o SRV.

I've heard fairly negative reports about TXT, so naturally this is a
concern.

 -Ekr
Received on Friday, 7 June 2013 16:45:24 UTC

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