Subject: [Sipping] [SIP] Call- IDs for same user

From: "Radhika" <[email-masked]>
Date: Wed, 3 Oct 2001 16:48:58 +0530

Hello,

In RFC 2543, it is mentioned that the same user issuing multiple REGISTER requests should have the same call-id (atleast within the same boot cycle). 

Consider the following scenario :

Computer1 (User A)                   Computer2 (User A)
( Callid = 1)                               ( Callid =2)                                                              
 ----------------                              -----------------    
I                l                             l                 l
I                l                             l                 l 
I                l                             l                 l     
I                l                             l                 l  
 ----------------                              ------------------
Registrations performed from each computer 

Computer 1 = R11, R12
Computer 2 = R21, R22

Regarding the same I have the following queries:
1) If the same user agent ( ie the same user ) logs in from 2 different computers, 2 REGISTER requests will be sent  ( may or may not be simultaneously ). In this case, should they have different call-ids ? (ie Callid = 1)

2)  Since multiple registrations are allowed from the same callid, the only distinguishing criteria between registrations from same callid will be the CSeq no. If a new registration is to be added by user A from Computer1, then it will have a higher CSeq no. 
But, if an already existing registration ( R11 of Callid = 1) needs to be refreshed before it expires, then a REGISTER request for the same needs to be issued. 

How do I distinguish between a new registration for the same callid, and registration renewal for an existing one? 
Can the CSeq for the original request and the renewal request be the same?

Thanks and regards,
Radhika.

---

From: "Bob Penfield" <[email-masked]>
Date: Wed, 3 Oct 2001 09:00:46 -0400

The part you are missing is the Contact header. Multiple registrations with
the same call-id, but different Contact headers will result in all of the
Contacts being registered. Incoming INVITEs will fork to all registered
Contacts. If the Contact(s) match existing registered Contacts, they are
updated. Registered Contacts are removed when they expire. The registrar
does not delete them if it notices they are missing from a subsequent
REGISTER request.

(-:bob

Robert F. Penfield
Chief Software Architect
Acme Packet, Inc.
130 New Boston Street
Woburn, MA 01801
[email-masked]

----- Original Message -----
From: "Radhika" <[email-masked]>
To: <[email-masked]>
Sent: Wednesday, October 03, 2001 7:18 AM
Subject: [Sipping] [SIP] Call- IDs for same user

Hello,

In RFC 2543, it is mentioned that the same user issuing multiple REGISTER
requests should have the same call-id (atleast within the same boot cycle).

Computer 1 = R11, R12
Computer 2 = R21, R22

Regarding the same I have the following queries:
1) If the same user agent ( ie the same user ) logs in from 2 different
computers, 2 REGISTER requests will be sent  ( may or may not be
simultaneously ). In this case, should they have different call-ids ? (ie
Callid = 1)

2)  Since multiple registrations are allowed from the same callid, the only
distinguishing criteria between registrations from same callid will be the
CSeq no. If a new registration is to be added by user A from Computer1, then
it will have a higher CSeq no.
But, if an already existing registration ( R11 of Callid = 1) needs to be
refreshed before it expires, then a REGISTER request for the same needs to
be issued.

How do I distinguish between a new registration for the same callid, and
registration renewal for an existing one?
Can the CSeq for the original request and the renewal request be the same?

Thanks and regards,
Radhika.

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