Re: [Stox] Stox-media: Should XEP-176 translations have Require: ice?

[Peter Saint-Andre <[e-mail]>]

On 3/25/14, 12:03 PM, Jonathan Lennox wrote:
>
> On Mar 25, 2014, at 1:37 PM, Emil Ivov <[e-mail]> wrote:
>
>> On 25.03.14, 15:15, Jonathan Lennox wrote:
>>>
>>> On Mar 25, 2014, at 4:55 AM, Saúl Ibarra Corretgé
>>> <[e-mail]> wrote:
>>>>>
>>>>>
>>>>>> It occurred to me that SIP has a way of saying "do ICE, or
>>>>>> fail the call": putting a "Require: ice" SIP option tag
>>>>>> (from RFC 5768) in the SIP INVITE.
>>>>>>
>>>>>> Should we recommend this?  It clearly has the right
>>>>>> semantics, and will prevent interop failure when a non-ICE
>>>>>> SIP endpoint answers a XEP-176 Jingle call.
>>>>>
>>>>> Theoretically that makes sense.
>>>>
>>>> Agreed. Maybe a gateway could do ICE on behalf of the non-ICE
>>>> capable endpoint, so can we say this is implementation specific
>>>> and thus add a MAY to it?
>>>
>>> Right, of course.  I was talking about how you’d want to handle a
>>> signaling-only gateway.
>>
>> There's also "XEP-0177: Jingle Raw UDP Transport Method" which is
>> basically equivalent to ICE-less SIP.
>>
>> That said, I don't mind mandating ICE at all.
>
> Right, but there’s no way for a Jingle client to offer a choice
> between XEP-176 and XEP-177, whereas RFC 5245 requires that both ICE
> and fallback non-ICE be supported.

Well, an XMPP initiator would not offer the ice-udp transport method if 
the responder didn't advertise support via XMPP service discovery (i.e., 
only advertised support for raw-udp). So, in general, fallback shouldn't 
really be necessary. However, we have defined a protocol flow for it 
just in case:

http://xmpp.org/extensions/xep-0176.html#fallback

Peter