Udit,

NOTIFY is required to end the impicit subscription that is created by the Transferor,
when it sends the REFER out.


Shekar

[EMAIL PROTECTED] wrote:

In the SIP CC Transfer, for failure transfer cases, why transferor sends INVITE(unhold) followed by BYE
on receiving NOTIFY (with failure status).


It can directly send BYE to Transferee. Is there any specific reason for doing this in the mentioned call flow.

5.3.1  Target Busy

             Transferor           Transferee             Transfer
                  |                    |                  Target
                  |                    |                    |
                  |            INVITE  |                    |
        Call-ID:1 |<-------------------|                    |
                  |            200 OK  |                    |
        Call-ID:1 |------------------->|                    |
                  |            ACK     |                    |
        Call-ID:1 |<-------------------|                    |
                  |  INVITE (hold)     |                    |
        Call-ID:1 |------------------->|                    |
                  |  200 OK            |                    |
        Call-ID:1 |<-------------------|                    |
                  |  ACK               |                    |
        Call-ID:1 |------------------->|                    |
                  |  REFER             |                    |
        Call-ID:2 |------------------->|                    |
                  |  202 Accepted      |                    |
        Call-ID:2 |<-------------------|                    |
                  | NOTIFY (100 Trying)|                    |
        Call-ID:2 |<-------------------|                    |
                  |            200 OK  |                    |
        Call-ID:2 |------------------->|                    |
                  |                    |  INVITE            |
        Call-ID:3 |                    |------------------->|
                  |                    |  486 Busy Here     |
        Call-ID:3 |                    |<-------------------|
                  |                    |  ACK               |
        Call-ID:3 |                    |------------------->|
                  |    NOTIFY (503 Service Unavailable)     |
                  | or NOTIFY (486 Busy Here)               |
        Call-ID:2 |<-------------------|                    |
                  |            200 OK  |                    |
        Call-ID:2 |------------------->|                    |
                  |  INVITE (unhold)   |                    |
        Call-ID:1 |------------------->|                    |
                  |  200 OK            |                    |
        Call-ID:1 |<-------------------|                    |
                  |  ACK               |                    |
        Call-ID:1 |------------------->|                    |
                  |  BYE               |                    |
        Call-ID:1 |------------------->|                    |
                  |  200 OK            |                    |
        Call-ID:1 |<-------------------|                    |


-Udit _______________________________________________ Sip-implementors mailing list [email protected] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors




begin:vcard
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n:Shekar;Nagesh
org:Lucent Technologies;Anypath Messaging System
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email;internet:[EMAIL PROTECTED]
title:Consultant
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tel;fax:+1-775-248-3937
tel;home:+1-614-864-3983
tel;cell:+1-614-316-0094
url:htpp://www.lucent.com
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