Nagesh,

My question was why Transferor is sending INVITE (unhold) when NOTIFY (486 
Busy) is received.
It can directly send BYE message.

-Udit



Nagesh Shekar <[EMAIL PROTECTED]> 
04/20/2005 06:35 PM
Please respond to
[EMAIL PROTECTED]


To
Udit Goyal/C/US/[EMAIL PROTECTED]
cc
SIP Implementors <[email protected]>
Subject
Re: [Sip-implementors] Failure transfer scenario






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
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>
>


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