Re: [sipcore] I-DAction: draft-mohali-sipcore-reason-extension-application-01

[Paul Kyzivat <[e-mail]>]

Marianne

On 3/4/2011 11:59 AM, [e-mail] wrote:
> Hi Paul,
>
> My answer below [MM]
>
> Marianne
>> -----Message d'origine-----
>> De : Paul Kyzivat [mailto:[e-mail]]
>> Envoyé : jeudi 3 mars 2011 18:31
>> À : MOHALI Marianne RD-CORE-ISS
>> Cc : [e-mail]; [e-mail]
>> Objet : Re: [sipcore] I-DAction:
>> draft-mohali-sipcore-reason-extension-application-01
>>
>> Marianne,
>>
>> On 3/3/2011 11:51 AM, [e-mail] wrote:
>>> Hi Paul,
>>>
>>> The purpose is to allow applications/services to be
>> explicitely identified in the signaling path, so that others
>> services/applications/telephony-AS can act accordingly.
>> Either to apply a process taking into account the service
>> interaction or on the contrary, do not execute a feature
>> already covered by the application.
>>> For instance, a caller with a prepaid service calls a
>> directory enquiries Server to ask for a restaurant phone
>> number. The operator would suggest to connect the caller to
>> the researched phone number EXCEPT if the caller has a
>> prepaid service because it is not sure he has enough credit
>> to pay for the communication. To allow this customized
>> feature, the directory enquiries Application needs to know
>> that the prepaid Application has been invocated.
>>
>> So once again, we are back to your wanting to use Reason not
>> to express a "reason" for anything, but rather as just a hook
>> to hang something on H-I.
> [MM] The *reason* why the call has been retargeted/rejected/modified is the invocation of a specific application.
> If you call a Service number and then the URI is changed for routing to the real destination, the *reason* of the URI modification (listed in H-I) is the application.

Based on your other replies, this is not necessarily so.

In fact the example above is a counter-example.
The prepaid service is not responsible for any redirection, and the 
operator service is looking for it for a reason other than that it has 
been the cause of anything. Its looking for it because it might be the 
cause of something in the future.

>> (With the causes you have defined, I can't imagine it making
>> *any* sense to actually use one in a Reason header in a
>> message, because they aren't specific enough to be actionable.)
>>
>> I am now thinking there is a large overlap between what you
>> are trying to accomplish this way, and what Christer is
>> trying to accomplish with draft-holmberg-sipcore-proxy-feature.
>>
>> Is that true?
>>
>> (Christer: What do you think?)
> [MM] I don't see the overlap with Christer's draft because it is not about capabilities, it is about what's happened.

In your example above, it seems that the operator service is looking for 
the prepaid service because the prepaid service has the capability to 
influence billing, or something like that. This seems at least somewhat 
in line with what Christer is advocating. Looking in the Route header, 
or Record-Route header would make at least as much sense for this case 
as looking in H-I. H-I makes sense if you are indeed looking for 
something that has already happened, perhaps on a path other that the 
current one.

I think it would be helpful for the two of you to come to some 
reconciliation of what you are trying to accomplish.

	Thanks,
	Paul

>>> About your comment in case of several applications involved
>> *simultaneously* in the call establishment, it is possible to
>> add 1 more hi-entry for the second application Cause you want
>> to be identified in the signaling path.
>>
>> Sure, you can indicate that they are "involved". But you
>> can't infer anything about which one "caused" something. They
>> might have, but you can't tell it from the presence of these headers.
>>
>> 	Thanks,
>> 	Paul
>>
>>> Regards,
>>> Marianne
>>>
>>>
>>>> -----Message d'origine-----
>>>> De : [e-mail]
>>>> [mailto:[e-mail]] De la part de Paul
>> Kyzivat Envoyé :
>>>> mardi 1 mars 2011 00:16 À : [e-mail] Objet : Re: [sipcore]
>>>> I-DAction:
>>>> draft-mohali-sipcore-reason-extension-application-01
>>>>
>>>> (As individual)
>>>>
>>>> Marianne,
>>>>
>>>> I'm still struggling to make sense of this in the form proposed.
>>>>
>>>> I look at the various cause values, and all the
>> descriptions are of
>>>> the form. E.g.:
>>>>
>>>>          Cause value: 2
>>>>          Reason text: Freephone
>>>>          Description: A Freephone application has influenced
>>>> processing of
>>>>          the call (e.g. by translating a dialed Free Phone
>> number to a
>>>>          routable directory number).
>>>>
>>>> I can't figure out how to make any actionable decision
>> based on this.
>>>> Rather, it seems I need to make a number of leaps of faith
>> before I
>>>> can decide what to do.
>>>>
>>>> For instance, if I get an error, it *might* be because I dialed a
>>>> freephone number, and it isn't supported from my calling location.
>>>> (E.g.
>>>> maybe I'm dialing [phone], but I'm doing so from
>> France, and
>>>> calling that number is only supported in the USA.
>>>>
>>>> But getting a application reason code with cause 2 doesn't really
>>>> tell me that is what happened. It could be that the call
>> indeed was
>>>> routed through a freephone application, and it properly routed the
>>>> call, and the call failed for some other reason. But the cause is
>>>> there because the application
>>>> *did* influence the call routing.
>>>>
>>>> Also, these "applications" are not, AFAIK, mutually
>> exclusive. E.g. I
>>>> could be using a prepaid service to make a directory
>> assistance call
>>>> that costs extra $$$ that I don't have credits to cover. But you
>>>> can't include two cause values for the same protocol. (But
>> it is true
>>>> that you
>>>> *can* have a number of servers each put one cause into
>>>> *their* H-I entry.)
>>>>
>>>> So *maybe* I would see that my call failed, and that there
>> is both a
>>>> reason indicating a prepaid application on one H-I entry,
>> and another
>>>> indicating a another H-I indicating a directory service
>> application.
>>>> But what can I conclude from that?
>>>>
>>>> Bottom line, I just can't make sense how this could be
>> used in a well
>>>> defined and interoperable way.
>>>>
>>>> 	Thanks,
>>>> 	Paul
>>>>
>>>> On 2/28/2011 9:58 AM, [e-mail] wrote:
>>>>> Hello,
>>>>>
>>>>> Here is the new version of the draft.
>>>>> Main changes are following:
>>>>> - More details about the registration procedure for new values
>>>>> - Clearer text in section 3.2
>>>>> - Add of Public and Private status for registered values.
>>>>> - Add of a range for cause values registration
>>>>>
>>>>> Best Regards,
>>>>> Marianne Mohali
>>>>>
>>>>> -----Message d'origine-----
>>>>> Objet : New Version Notification for
>>>>> draft-mohali-sipcore-reason-extension-application-01
>>>>>
>>>>> A New Internet-Draft is available from the on-line
>> Internet-Drafts
>>>>> directories.
>>>>>
>>>>> 	Title           : Extending the Session Initiation Protocol
>>>>> (SIP) Reason Header for Applications
>>>>> 	Author(s)       : M. Mohali, B. Chatras
>>>>> 	Filename        :
>>>>> draft-mohali-sipcore-reason-extension-application-01.txt
>>>>> 	Pages           : 10
>>>>> 	Date            : 2011-02-24
>>>>>
>>>>> This document defines a new protocol value "Application" for the
>>>>> Reason Header field and a new IANA Registry for registering
>>>>> application types.  This new value enables signaling that a
>>>> request or
>>>>> response has been issued as a result of a decision made by a
>>>>> particular type of application or that an initial request
>> has been
>>>>> retargeted as a result of an application decision.
>>>>>
>>>>> A URL for this Internet-Draft is:
>>>>>
>>>>
>> http://www.ietf.org/internet-drafts/draft-mohali-sipcore-reason-exten
>>>> s
>>>>> io
>>>>> n-application-01.txt
>>>>>
>>>>> Internet-Drafts are also available by anonymous FTP at:
>>>>> ftp://ftp.ietf.org/internet-drafts/
>>>>>
>>>>> Below is the data which will enable a MIME compliant mail reader
>>>>> implementation to automatically retrieve the ASCII version of the
>>>>> Internet-Draft.
>>>>>
>>>>>
>>>>
>> <ftp://ftp.ietf.org/internet-drafts/draft-mohali-sipcore-reason-exten
>>>> s
>>>>> io
>>>>> n-application-01.txt>
>>>>>
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