Subject: [Sipping] Question on REFER usage

From: Darshan Bildikar <[email-masked]>
Date: Thu, 04 Aug 2005 18:10:03 +0800

I had posted a question on REFER usage sometime ago to the
sip-implementors list. I think it might be better suited to the SIPPING
list. So here goes.

Basically what I need is a way to make a "post-dated" REFER i.e. what if
I need a REFER not to be effective immediately. 

Say I want a nifty service in my Presence Client that will help me
configure that I want some of my friends to be called up and wished on
their birthdays or special occasions. Or say that I know (on a Friday)
that I need to talk to someone on Monday morning. A long standing REFER
would connect me to this person that I need to talk to WHEN I want to
talk to him. I can be sure that I wouldn't forget to call then! I think
it's a neat feature. 

Could this be done by defining new headers for REFER. 

If not, the only way out seems to be a NON-SIP interface between my
client and server.

Doing it when I'm online or on a need basis is easy. What if I just want
to do a one time configuration and then log off. When the call is made
the result can be notified to me (If I am online). I can't obviously
store this information in my client because I might not be online when
the event occurs. 

There was a discussion some time ago on long running subscriptions and
whether a NOTIFY can go out of a dialog. Not really sure what happened
with that. 

Darshan

Sip-implementors mail exchange.

-----Original Message-----

From: Paul Kyzivat [mailto:[email-masked]] 

Sent: Thursday, August 04, 2005 5:19 PM

To: Darshan Bildikar

Cc: 'Banibrata Dutta'; [email-masked]

Subject: Re: [Sip-implementors] Question on REFER

If there were such a capability, then it would require the recipient of 

the refer to maintain state until the due date of the REFER. Making the 

recipient keep state for an arbitrarily long time seems like a really 

bad idea. If you really want this to happen then you probably don't want

to trust the recipient to store that state.

So I think this is a bad idea.

      Paul

Darshan Bildikar wrote:

> Sending a REFER every time is exactly what I want to avoid. The

example

> I used to illustrate was probably not right.

> Let's take conferencing as an example. I know that there is a

conference

> taking place say on the 15'Th of August. I know I want users A and B

to

> join the conference. I want to send them a REFER right NOW, saying

JOIN

> this conference on the 15'th of August (I'd be sending this REFER to

the

> Server).

> Or I have an application in which I want 20 of my friends to be called

> up automatically and be wished on their birthdays. It's a one time 

> setting for me and I might not even be online when I need to send the 

> REFER.

> That's why I need to send the REFER right now! Not when the actual

event

> occurs because I'm not even sure when that'll happen.

> Essentially what I need is to give a "post-dated" REFER and persist

the

> subscription state. I might want to deal / not deal with the 

> notifications to this.

> Darshan

> -----Original Message-----

> From: Banibrata Dutta [mailto:[email-masked]]

> Sent: Wednesday, August 03, 2005 8:30 PM

> To: 'Darshan Bildikar'; [email-masked]

> Subject: RE: [Sip-implementors] Question on REFER

> Hi Darshan:

> In this case you need to send the REFER each time you want to play the

> announcement at 7:00AM. The implicit subscription created by the REFER

> will provide you events that

> tell you about

> the completion of such a call and it's clearing. Once the call is

> established with the IVR/IP

> and terminated, to recreated this call you'd have to send a REFER

again.

> The

> call clear would

> terminate the implicit subscription too.

> If the Application Server is doing this, you don't have to care if it 

> needs to remember to

> send this REFER everyday at 7:00AM.

> regards,

> banibrata.

> -----Original Message-----

> From: [email-masked]

> [mailto:[email-masked]] On Behalf Of Darshan

> Bildikar

> Sent: Wednesday, August 03, 2005 4:22 PM

> To: [email-masked]

> Subject: [Sip-implementors] Question on REFER

> As we know the REFER method is used to refer a user to another URI.

> But what if I need that the referral need not to be effective 

> immediately i.e. I want to send a REFER now but request A to connect 

> to B at a particular point in time.

> This would be useful in applications where I need to make a system 

> initiated call or just need to initiate a call to a user and play a 

> pre recorded announcement. For example, call a user everyday at 7:00 

> AM and play

out

> a

> pre recorded song to him.

> Is REFER the right way to do this. Since my refer subscription is

going

> to

> be a long running one I need to figure out a way to keep it in a 

> persistent data store, not in memory.

> Any thoughts/comments appreciated.

> Darshan

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---

From: "Dale Worley" <[email-masked]>
Date: Thu, 4 Aug 2005 13:10:54 -0400

Why not add the ability to keep track of "people to call in the future" as a
feature of your Presence Client?  That would have a number of advantages --
not making SIP more complex, not requiring other SIP agents in the system to
keep long-term state, and best of all, since it's in your Presence Client,
the P.C. will wait until you are present before making the call!

Dale
  -----Original Message-----
  From: [email-masked] [mailto:[email-masked]]On Behalf
Of Darshan Bildikar
  Sent: Thursday, August 04, 2005 6:10 AM
  To: [email-masked]
  Subject: [Sipping] Question on REFER usage

  Basically what I need is a way to make a "post-dated" REFER i.e. what if I
need a REFER not to be effective immediately.

  Say I want a nifty service in my Presence Client that will help me
configure that I want some of my friends to be called up and wished on their
birthdays or special occasions. Or say that I know (on a Friday) that I need
to talk to someone on Monday morning. A long standing REFER would connect me
to this person that I need to talk to WHEN I want to talk to him. I can be
sure that I wouldn't forget to call then! I think it's a neat feature.

  If not, the only way out seems to be a NON-SIP interface between my client
and server.

  Doing it when I'm online or on a need basis is easy. What if I just want
to do a one time configuration and then log off. When the call is made the
result can be notified to me (If I am online). I can't obviously store this
information in my client because I might not be online when the event
occurs.

  There was a discussion some time ago on long running subscriptions and
whether a NOTIFY can go out of a dialog. Not really sure what happened with
that.

  Darshan

  -----Original Message-----

  To: Darshan Bildikar

        Paul

  example

  conference

  to

  JOIN

  the

  event

  the

  again.

  out

  going