Subject: [Sipping] User Preferred Contact Address

From: "Aisling O'Driscoll" <[email-masked]>
Date: Tue, 19 Jul 2005 21:51:42 +0100

Hello all,

I am hoping to get opinions on the below:

I am considering research options in either extending CPL to support a
REGISTER messages (some research has been done with CPL & SUBSCRIBE
messages for presence) or perhaps adding a field to a SIP REGISTER
message?...any other suggestions also welcome.

The reason I am considering the above is because I would like a user
to be able to choose their preferred SIP end device to have a call
delivered to e.g. office hard phone or pda softphone, laptop
softphone etc. This user would have registered many times
from the various end user devices with the same url and would
therefore have multiple contact addresses. I cannot think how I can
associate a particular contact address with "office phone" or
"laptop" etc. 

However if I could extend CPL script syntax for this or perhaps add
an extra field in a sip register message indicating the place the
contact address is associated with, could this could work?

I cannot think of other methods of implementing this scenario. The
problem with extending a SIP REGISTER message is that it would
require every user to have a dedicated client. Anything I could do
purely on the service provider side?

Many thanks for your ideas and guidance,
BR,
Aisling O' Driscoll.

-------------------Legal  Disclaimer---------------------------------------

The above electronic mail transmission is confidential and intended only for the person to whom it is addressed. Its contents may be protected by legal and/or professional privilege. Should it be received by you in error please contact the sender at the above quoted email address. Any unauthorised form of reproduction of this message is strictly prohibited. The Institute does not guarantee the security of any information electronically transmitted and is not liable if the information contained in this communication is not a proper and complete record of the message as transmitted by the sender nor for any delay in its receipt.

_______________________________________________
Sipping mailing list  https://www1.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP
Use [email-masked] for questions on current sip
Use [email-masked] for new developments of core SIP

---

From: Paul Kyzivat <[email-masked]>
Date: Tue, 19 Jul 2005 18:27:16 -0400

Aisling,

Similar things have been discussed recently. (See 
draft-jennings-sipping-instance-id-01.txt) To identify particular 
endpoints uniquely, the +sip.instance feature tag has been proposed. It 
isn't especially user-friendly but it is unique.

You could define, somewhere, a mapping between sip.instance values and 
user-friendly names.

You could also define a different feature tag for the express purpose of 
providing a friendly name for a contact, but then you run the risk of it 
not being unique, and of requiring a way to provision the device with 
the value.

	Paul

---

From: "Dale Worley" <[email-masked]>
Date: Wed, 20 Jul 2005 09:56:19 -0400

> From: Aisling O'Driscoll
> delivered to

Why not have that device register with "q=1" and all the other devices
register with "q=0.8".  That will route all calls to the first device first,
but they will still fall back to the other devices if the first does not
answer.

Dale

---

From: "Aisling" <[email-masked]>
Date: Wed, 20 Jul 2005 16:48:55 +0100

Hi,

Thanks for the reply.

I would rather if all the devices did not have to re-register every time
the user wanted to change the order of devices to which a call should be
directed. If there are multiple users and they all change their minds 10
times a day about the order of their end devices, I would suspect this
cause a large amount of unnecessary traffic.

Also this would require the user having some knowledge of the network to
set the q value. I would like the user to simply be able to choose
"office hard phone" or "laptop softphone" from an interface. NB -
There's no way for the system to know by looking at the user location
details which contact address is supposed to be "laptop softphone" in
order to modify the q value to be the highest. 

I'd greatly appreciate any further thoughts on this,
Many Thanks,
Aisling.

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of Dale Worley
Sent: 20 July 2005 14:56
To: [email-masked]
Subject: RE: [Sipping] User Preferred Contact Address

Why not have that device register with "q=1" and all the other devices
register with "q=0.8".  That will route all calls to the first device
first,
but they will still fall back to the other devices if the first does not
answer.

Dale

-------------------Legal
Disclaimer---------------------------------------

The above electronic mail transmission is confidential and intended only
for the person to whom it is addressed. Its contents may be protected by
legal and/or professional privilege. Should it be received by you in
error please contact the sender at the above quoted email address. Any
unauthorised form of reproduction of this message is strictly
prohibited. The Institute does not guarantee the security of any
information electronically transmitted and is not liable if the
information contained in this communication is not a proper and complete
record of the message as transmitted by the sender nor for any delay in
its receipt.

---

From: "Dale Worley" <[email-masked]>
Date: Thu, 21 Jul 2005 12:55:10 -0400

> From: Aisling [mailto:[email-masked]]
>
> directed.

Actually, only 2 devices need to re-register, the one that is no longer the
preferred device, and the one that is becoming the preferred device.
(Because the q value for other devices remains unchanged.)

> If there are multiple users and they all change
> their minds 10

Usually, devices register for 3600 seconds (1 hour) at a time, so the
increase in traffic would probably not be large.

> set the q value.

Well, they'd have to have some concept of q values, or the device's UI would
have to have that knowledge for them.  But the q values specified for the
contacts of one AOR do not interact in any way with the q values for the
contacts of any other AOR.

> I would like the user to simply be able to choose
> "office hard phone" or "laptop softphone" from an interface.

Nonetheless, I can see that it would be more user-friendly to select an item
from a menu than to order one device to register itself as no longer being
the preferred device and then order another device to register itself as the
preferred device.

> NB -

True.  As someone suggested, it is coming into fashion to use the
"+sip.identity" parameter to provide a unique ID for every device.  Failing
that, an application could send an OPTIONS request to the device and examine
the User-Agent header in the response.

Dale