Subject: RE: [Sipping] Call Waiting - who does the tone (round 2)

From: "Dusan Mudric" <[email-masked]>
Date: Fri, 20 Jun 2003 10:26:38 -0400

Exactly. 
 
That was basic assumption. I was just trying to show that it is possible to make it controllable by service provider. I didn't want to stream discussion into this direction assuming concept of service control is well understood.
 
Regards,
Dusan Mudric.
 
-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Friday, June 20, 2003 10:13 AM
To: [email-masked]; Dusan Mudric
Cc: [email-masked]; [email-masked]; [email-masked]; [email-masked]
Subject: Re: [Sipping] Call Waiting - who does the tone (round 2)
 
In a message dated 6/19/2003 1:28:51 PM Eastern Standard Time, [email-masked] writes: 

Dusan, 

Every SIP phone that I am aware of offers call waiting natively. It 
requires no cooperation on the part of any service provider, and no 
additional cost by either the end-user nor by any service provider. 

- Nobody has provided any compelling benefit to the end-user to do call 
waiting in the network 
- Nobody has provided any compelling benefit to the service provider to 
do call waiting in the network 
- Nobody has demonstrated that any SIP phones implement any of the 
additional weirdo mechanism that would be required to make network call 
waiting work as well as locally-implemented call waiting, Nor that 
there is any compelling economic reason for them to do so. 

thanks, 
-rohan 

Rohan, 

I've been watching this discussion hoping to see a good answer to the beginning question: "Who does the tone?" since this same question about the source of tones comes up in many other areas, such as the Assured Service that we require. Maybe I missed something, but I don't think I've heard an answer - just lots of conjecture and possibilities of how it might be done. 

As for the question above - what is the benefit to the service provider to doing call waiting in the network?- I'll try to address that one. 

It's not a question of "where" it's done, but of who controls it. In the case I am interested in, the network provider/service provider/end users (really all the same large bunch of people) want a system which offers a number of services, including Call Waiting and Assured Service. Part of the requirement is to provide certain operational interactions between those services. That is, there is an expectation of which service takes precedence when multiple services may apply at the same time. If Call Waiting is done completely in the UA, and Call Forwarding is done in a proxy, and the decision to preempt a call for Assured Service is done someplace else, there is no way that I can imagine that the service provider would have any control whatsoever over the precedence of these actions or other interactions between them. So the requirement for this network is going to be that all services applying to a terminating call must be controlled by a single device, I guess it would be a SIP proxy serving the called user. The service provider requires standardized ways to do all of the required services, controlled by a proxy. Without that, it can not use SIP. 

Mike Pierce

---

From: "Rosen, Brian" <[email-masked]>
Date: Fri, 20 Jun 2003 10:42:39 -0400

Mike

Most SIP Phones handle multiple call appearances.  Some don't.
For the ones that do, "Call Waiting" isn't a useful service;
it's clearly handled in the phone.  At the moment, I don't even 
think there is way for a system to even know if a phone can 
actually handle multiple call appearances.

With that reality, I think that the requirement is that the
phone do something reasonable when it gets an INVITE from another
UA while it has an existing session.  It might light a light,
ring the ringer, play a tone, or shake, but it does
something that alerts the user that another call is available.

The call assurance service would have to work with phones
that handle multiple call appearances.  Whatever you decide
to do with them would apply equally to a phone that only
handles one call, but plays a tone when another INVITE
arrives.  There are no significant differences.

Brian

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
Sent: Friday, June 20, 2003 10:13 AM
To: [email-masked]; [email-masked]
Cc: [email-masked]; [email-masked]; [email-masked];
[email-masked]

In a message dated 6/19/2003 1:28:51 PM Eastern Standard Time,
[email-masked] writes: 

Dusan, 

thanks, 
-rohan 

Rohan, 

I've been watching this discussion hoping to see a good answer to the
beginning question: "Who does the tone?" since this same question about the
source of tones comes up in many other areas, such as the Assured Service
that we require. Maybe I missed something, but I don't think I've heard an
answer - just lots of conjecture and possibilities of how it might be done. 

As for the question above - what is the benefit to the service provider to
doing call waiting in the network?- I'll try to address that one. 

It's not a question of "where" it's done, but of who controls it. In the
case I am interested in, the network provider/service provider/end users
(really all the same large bunch of people) want a system which offers a
number of services, including Call Waiting and Assured Service. Part of the
requirement is to provide certain operational interactions between those
services. That is, there is an expectation of which service takes precedence
when multiple services may apply at the same time. If Call Waiting is done
completely in the UA, and Call Forwarding is done in a proxy, and the
decision to preempt a call for Assured Service is done someplace else, there
is no way that I can imagine that the service provider would have any
control whatsoever over the precedence of these actions or other
interactions between them. So the requirement for this network is going to
be that all services applying to a terminating call must be controlled by a
single device, I guess it would be a SIP proxy serving the called user. The
service provider requires standardized ways to do all of the required
services, controlled by a proxy. Without that, it can not use SIP. 

Mike Pierce 

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---

From: [email-masked]
Date: Fri, 20 Jun 2003 17:16:09 EDT

In a message dated 6/20/2003 1:52:17 PM Eastern Standard Time, 
[email-masked] writes:

> Are you suggesting that SIP become a (Proxy) Server controlled Protocol (of 
> UAs) before you'll use it?
> 
> I hope I misunderstood the last bit of your paragraph above
> 

No, I think you understood what I said perfectly. I am saying, as others 
already have, that the only way in which SIP can be used in a "carrier" 
environment such as the one I represent is with SIP proxies, controlled by the service 
provider, in charge of providing and controlling end-user services. Please read 
draft-pierce-ieprep-assured-service-arch-00.

Please understand though, I am not saying that "SIP become a (proxy) server 
controlled protocol." I am saying that it must be used in that way in the 
network I'm talking about. I have never argued that the alternative (without SIP 
proxies) can not be used in some networks to provide a full range of services 
(although I'm waiting to see it).

Mike Pierce

---

From: [email-masked]
Date: Mon, 23 Jun 2003 11:58:25 +0300

A call stateful proxy can decide to forward or not to forward an INVITE to a UA that is already in another call. The decision can be based on anything including charging ( a user has payed for call forwarding). If the proxy decides to forward the INVITE, it is the UA that plays the tone when it receives the INVITE.

Network controls the service, UA DOES the tone.

Did I miss anything?

/Hisham

-----Original Message-----
From: ext [email-masked] [mailto:[email-masked]]
Sent: Friday, June 20, 2003 5:13 PM
To: [email-masked]; [email-masked]
Cc: [email-masked]; [email-masked]; [email-masked]; [email-masked]
Subject: Re: [Sipping] Call Waiting - who does the tone (round 2)

Dusan, 

thanks, 
-rohan 

Rohan, 

Mike Pierce