[SIPForum-techwg] IP PBX section 15

[Francois Audet]

Yes, I agree that it has a bigger impact on SIP clients than PBXs.
I guess IP PBXs have embedded gateways, but I do agree.

On Jan 10, 2006, at 23:58 , Elwell, John wrote:

> Francois,
>
> I agree with all that Paul said.
>
> Furthermore, this is sounding more and more to me like an issue  
> that should
> be dealt with in the SIP devices work item, not the PBX-SP work  
> item. It has
> nothing to do with the PBX-SP interface.
>
> John
>
>> -----Original Message-----
>> From: Francois Audet [mailto:audet at nortel.com]
>> Sent: 11 January 2006 01:32
>> To: Paul Kyzivat
>> Cc: Joanne McMillen; Elwell, John; SIP Forum Tech WG; Chris Sibley
>> Subject: RE: [SIPForum-techwg] IP PBX section 15
>>
>>
>>> Francois,
>>>
>>> I take your point about hanging up for dead silence. But it
>>> definitely
>>> shouldn't play ringback. My jest about playing relay clicking
>>> sounds may
>>> be taken seriously if you like.
>>
>> I think that's up to the manufacturer to decide.
>>
>> Ringback is probably the only tone that the user will not
>> interpret as an error and hang-up the call.
>>
>> So if you want the user to "not hang-up" you are probably stuck with
>> ringback. In any case, I think the current wording about "some form
>> of progress tone" is fine.
>>
>>> More significantly, this has nothing to do with whether there
>>> was SDP in
>>> the 183. It has to do with whether there is data being
>>> received on the
>>> RTP stream or not. You can receive ringback without having
>>> received SDP
>>> in a 183, and you can not be receiving ringback even if you
>>> did get SDP
>>> in a 183.
>>
>> Yes, this is a good point (even if many implementations are
>> incapable of doing what you suggest, it is probably better).
>>
>>> In any case, I think this is really a human factors issue and
>>> a quality
>>> of implementation issue for the UA. I don't think it belongs as a
>>> requirement here.
>>
>> I'm not sure about this. I can see lots of people pointing fingers
>> at each other the first time "dead silence" occurs...
>>
>> Maybe we just need to say something about playing appropriate
>> tones in the event that a progres cause is received, but no
>> media is available.
>>
>