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

[Paul Kyzivat <[e-mail]>]

On 3/7/2011 1:29 PM, [e-mail] wrote:
> Paul,
>
> I think that Christer's draft (proxy-feature) is about capabilities while this one (reason-extension-application) is about what really happened (like reason in general). It is provided only when the event happens and the purpose is to give an accuate information for applicative events.
>
> Let me give you an other example:
> A reception AS called with several premium rate numbers (1 per hosted application/service).

I'm sorry, but I'm not familiar with such services, so I don't fully 
understand this, though I can guess. Here is what I think you are saying:

There are some special URLs (premium rate numbers) that I can call.
A property of these is that when I call them my call is charged extra.
(I guess perhaps these are what we call "900" numbers in the US.)

Such calls are routed to a special server which handles this premium 
rate charging. When it receives an INVITE to a premium rate URL that it 
supports, it regargets the URL to a different one denoting the actual 
server, and then forwards the INVITE.

The ultimate server wants a way to determine whether a premium rate URL 
was used in reaching this server, and if so, which one.

And I suppose there may have been multiple translations, and so the goal 
is to identify one that was done by a premium rate server.

> The AS dispatches calls to several call centers (eg. Depending on charge, hour of the day/night...). The final destination needs to know the called service.

> The premuim rate number should be listed in the H-I header. Which entry? For which application/service invocated?
> As you can have a call forwarding reason associated to a 3xx or 486 Reason-cause, you could have an applicative reason to easily identify the premium rate dialed number.

So you want to have an indication that the cause of the retargeting was 
"premium rate", or "premium rate server" or "premium rate service".

But frankly it doesn't sound like that is the reason for the 
retargeting. The reason for retargeting is that the address given 
terminated on something that delegates the actual work. It could as well 
have been a registrar, to which the actual services register.

ISTM that the URL has the property that calling it costs extra, or else 
its the behavior of the AS that it first landed on that charges a 
premium rate. Isn't it equally possible that the AS could have provided 
the service directly rather than retargeting.

If the AS actually does the billing, and needs to be in the route to do 
so, then Christer's proposal might make sense.

If its the ultimate recipient that does the billing, and does so based 
on the particular URL used to reach it, then its perhaps just the 
presence of that URL along the path that matters, and maybe even if the 
call was redirected.

If the URL called determines the service delivered and the price, why 
does it matter whether the retargetting was via a premium rate service 
or not? Wouldn't the server just look through the H-I at all the 
retargetings until it got to one that identifies a service it supports? 
If so, it wouldn't need a cause code at all.

	Thanks,
	Paul

> Regards,
> Marianne
>
>
>> -----Message d'origine-----
>> De : Paul Kyzivat [mailto:[e-mail]]
>> Envoyé : lundi 7 mars 2011 01:42
>> 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 3/4/2011 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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>>
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