Re: Allowing RTCIceServer to contain multiple URLs

On Fri, May 31, 2013 at 1:44 PM, Eric Rescorla <ekr@rtfm.com> wrote:

>
> 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
>
>
I personally think S-NAPTR could work here, but there are two trade-offs to
consider:

S-NAPTR targets are domain names, which means you may incur a round-trip in
discovering the associated addresses for the domain names.  In some cases,
they are pointers to services which also require S-NAPTR look ups (see
section 4.3 of RFC 3958 for an example); those may incur two round trips.
There are ways to optimize this, but it can incur extra latency.

S-NAPTR (and other DDDS approaches) really give you two things:  data about
what's available and data about the ordering that is preferred by the
service owner.  While that might come into play here, I have heard a use
case for it.  Is there one?

regards,

Ted