On 06/04/2008 9:00 AM, Paul Witty wrote:
> Peter Saint-Andre wrote:
>> This is the first in my series of posts on Jingle. More soon.
>>
>> According to version 0.25 of XEP-0166, use of the content-replace action
>> is forbidden during the PENDING state. However, XEP-0176 (ICE-UDP) uses
>> the content-replace action during the PENDING state:
>>
>> http://www.xmpp.org/extensions/xep-0176.html#protocol-acceptance
>>
>> In XEP-0176, this usage maps to nomination of the candidates to be used
>> in ICE, see section 2.6 of draft-ietf-mmusic-ice-19.
>>
>> However, in ICE this nomination is done over STUN, not via SIP/SDP.
>> Therefore I think the content-replace action is unnecessary in XEP-0176
>> (since nomination in the Jingle ICE-UDP transport will also occur over
>> STUN and does not need to happen in the signalling channel).
>>
>> Unless there are objections, I will update XEP-0176 accordingly (a usage
>> inherited by some of the examples in XEP-0167 and XEP-0180, which will
>> be harmonized with the modified XEP-0176).
>>
>> Peter
>>
>>   
> Can I just get a bit of clarification about how the initiation should
> work, and what part the user plays in accepting the session.  If the
> session-accept is only sent upon successful completion of ICE, does this
> mean that the user should only be alerted about the incoming session
> after ICE is complete, to prevent them accepting a session for which the
> session-accept will never actually be sent because there are no
> acceptable candidates?

The protocol-level session-accept is different from the user-level
button-click involved in making a go/no-go decision about whether the
user wants to "pick up the phone" or whatever. I imagine that the client
will show the user some kind of interface that requires user interaction
to approve the session request after sending the initial ack of the
session-initiate and before sending the session-accept. However I
suppose that the client should not send the session-accept before the
user has had a chance to click the big "accept this call" button.

> Also, when it comes to to sending the session-accept, the completion of
> ICE means that we have already accepted a candidate, so explicitly doing
> so in the session-accept is redundant.  A correct implementation of ICE
> will never choose a candidate which will not work for both parties, so
> we will never reach the error state in Example 10 of section 5.6.

We will never reach that error state or we should never reach that error
state? I like to spec out all eventualities, even if we never "should"
get to that point.

Peter

-- 
Peter Saint-Andre
https://stpeter.im/

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