Subject: Re: [Ice] ice-options in draft-ietf-ice-rfc5245bis and draft-ietf-ice-trickle

From: Peter Saint-Andre <[email-masked]>
Date: Thu, 1 Feb 2018 13:07:14 -0700

On 1/31/18 9:47 PM, Ben Campbell wrote:
> Thanks for your quick response, Peter; this discussion was
> helpful—partially by bringing up a separate but related question
> (more for 5245bis than for ice-trickle):
> 
> Section 13 of 5245bis talks about a series of tokens for
> “ice-options”. But since the ice-options  SDP attribute in no longer
> defined in 5245bis, did we lose the text that says that the ICE
> option needs to be able to carry multiple tags, whatever the
> signaling protocol is?

I don't want to speak for the 5245bis authors, but it strikes me that
the exact form of "the ICE option" will depend on the signaling
protocol. That is, it's not necessarily the case that syntactically the
signaling protocol will define a single construct for "the ICE option"
that itself can include "multiple tags" - that syntax might be true for
SDP but not other signaling protocols. For instance, in XMPP (for which
we still need to update the relevant Jingle transport method [1]), the
fact that an entity supports "ice2" and "trickle" will be signaled by
advertising the 'urn:xmpp:jingle:transports:ice:0' XML namespace
(whereas support for pre-ice2 is signaled by advertising the older
'urn:xmpp:jingle:transports:ice-udp:1' namespace' defined in XEP-0176).

Peter

[1] https://xmpp.org/extensions/xep-0371.html

---

From: Ben Campbell <[email-masked]>
Date: Thu, 1 Feb 2018 14:51:08 -0600

> On Feb 1, 2018, at 2:07 PM, Peter Saint-Andre <[email-masked]> wrote:
> 
> SDP but not other signaling protocols.

Sure, I guess I meant this more conceptually than syntactically. But if an application supports, for example, no ice, 5245bis, or 5425bis with trickle, then you need to be able to distinguish between those. (Not to mention if they support 5245 legacy as a separate mode.)

> For instance, in XMPP (for which

IIRC, Jingle assumes trickle if you support ICE, correct?

---

From: Peter Saint-Andre <[email-masked]>
Date: Thu, 1 Feb 2018 13:53:47 -0700

> Sure, I guess I meant this more conceptually than syntactically. But if an application supports, for example, no ice, 5245bis, or 5425bis with trickle, then you need to be able to distinguish betwe…

Indeed.

> IIRC, Jingle assumes trickle if you support ICE, correct?

Yes, that's been the primary data transfer method in Jingle since the
beginning.

Peter