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Re: Allowing RTCIceServer to contain multiple URLs

From: Eric Rescorla <ekr@rtfm.com>
Date: Fri, 31 May 2013 13:44:51 -0700
Message-ID: <CABcZeBOV5bKqErakZRWeMftOgbd5WLV_MxOUqAG5LdXXFMW86A@mail.gmail.com>
To: Justin Uberti <juberti@google.com>
Cc: Martin Thomson <martin.thomson@gmail.com>, "public-webrtc@w3.org" <public-webrtc@w3.org>, Mallinath Bareddy <mallinath@google.com>
On Wed, Apr 24, 2013 at 9:34 PM, Justin Uberti <juberti@google.com> wrote:

> I wasn't suggesting that you couldn't have multiple RTCIceServers -
> clearly that's something we still want to support.
>
> The idea was mainly to indicate a specific TURN server could be reachable
> via different protocols - while that can be accomplished via multiple
> RTCIceServers, it might not be desirable to try to use all protocols at
> once and allocate 3 TURN candidates (e.g. for UDP, TCP, and TLS). If there
> were multiple transports available for a single TURN server, TCP and TLS
> could be ignored if UDP worked (i.e. and only a single candidate would be
> allocated).
>
> Agree this may not be needed if we can rely on using S-NAPTR to look up
> the TURN server addresses, but is this widely deployed today?
>
>
I agree with Justin that it's highly desirable to be able to have the
semantics that
this is a single TURN server which is reachable via three mechanisms rather
than three separate TURN servers, since I only really want to be connected
to one of them.

I am not enough of an expert on DNS to know if S-NAPTR is practical here,
but I've certainly heard plenty of complaints about how all but the most
basic
DNS features don't work. Do we have measurements about the accessibility
of S-NAPTR from browser-class endpoints?

-Ekr


>
>
> On Wed, Apr 24, 2013 at 10:50 AM, Martin Thomson <martin.thomson@gmail.com
> > wrote:
>
>> On 23 April 2013 23:06, Justin Uberti <juberti@google.com> wrote:
>> > So to do this using the existing RTCIceServer syntax, one must create
>> > separate RTCIceServer objects for each URI, all with the same
>> credentials.
>> > It seems like it would be cleaner to allow a list of URIs to be
>> supplied in
>> > a RTCIceServer, which would all share the same credentials. To achieve
>> this,
>> > we could simply change the current .url property from a DOMString to a
>> list,
>> > or add a new .urls property that is a list of DOMStrings.
>>
>> > Any objections?
>>
>> Yeah, what Cullen said, plus: if you have multiple URIs with the same
>> credentials, make multiple RTCIceServers.  It's not especially hard:
>>
>> var iceServers = stunServers.concat(turnUris.map(function(turnUri) {
>> return { url: turnUri, credential: cred, username: user }; }));
>>
>
>
Received on Friday, 31 May 2013 20:45:58 UTC

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