Re: [Sipping-tispan] [CCBS/CCNR]

[Miguel Garcia <[e-mail]>]

Paul Kyzivat wrote:


> 
>>>> With respect your question, then probably we need to define what "no 
>>>> reply" means, in which case, I would say that "no reply" is the 
>>>> event when the session is properly delivered to the callee never 
>>>> answers. Note that this has nothing to do with "no logged in", or 
>>>> any 4xx, 5xx, or 6xx responses. It just that, e.g., an INVITE is 
>>>> properly answered with a 1xx response, but no other response is 
>>>> received within a period of time.
>>>
>>>
>>> It could also be that there is no phone registered, which would 
>>> result in a 480 response. I think that probably should also be 
>>> considered a No-Response case.
>>
>>
>> I think the service is clearly focusing on the "no reply", so you are 
>> registered, but don't answer. If the phone is not registered, I think 
>> there can't be any completion of call, unless you subscribed to the 
>> presence information of the callee and monitor when he becomes 
>> registered.
> 
> 
> This is a case where the environments are so dissimilar that we need to 
> be careful to figure out what the proper analogy is.
> 
> In the case of analog phone service, if you unplug your phone and 
> someone calls I think it would be treated as a no-answer case. Now if 
> you switch to sip phones, and you unplug the phone, it will be a 
> not-registered case. From the caller's perspective the situation is the 
> same, and this is a primarily a caller facing feature. So I think this 
> should probably be part of the same service. I'd be interested to hear 
> other opinions.

That's true... I am also interested in hearing other opinions. But as I 
said before, in GSM and DECT (european cordless) there is a similar 
service call Call Forwarding on User Not-Logged In. So clearly the 
service separates the not-logged in feature from the no reply.

> 
> Watching the reg event package would then be required to know when to 
> try again. It would be an excellent indicator that someone is present to 
> respond. (Though not a perfect indicator. It could just be a device that 
> had power restored to it.)

Agree.

> 
> This isn't the only case that is going to require use of the reg event. 
> Use of the dialog package will also need the reg package to discover the 
> UAs at which a subscription to dialog is needed.
> 
>> There is a similar service, called Call Forwarding on not-logged in 
>> (or something similar), which is not applicable to the PSTN, but to 
>> mobile and cordless networks.
> 
> 
> I don't believe that is a similar service. It is more of a callee 
> oriented service - providing the callee with a backup service when their 
> primary device(s) aren't available.

True, it is a calee oriented service. My whole point is that there is a 
service that differentiates the states "no reply" from "not-logged in". 
Once you have differentiated the states, then you can apply services to 
the caller (Call complibation on...) or the callee (Call forwarding on...)

/Miguel


> 
>     Paul

-- 
Miguel A. Garcia           tel:[phone]
sip:[e-mail]
Nokia Research Center      Helsinki, Finland


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