On 4/26/2011 1:09 PM, isshed wrote:
> Thanks Dale for your response. so the other doubt is what will happed to
> this dialog when the call gets transferred. does it not get destroyed with
> the BYE? if so what about the rest of the notify?
You should read 5057 on dialog usages - you need to understand that.
When you send a REFER in a dialog with an existing invite-dialog-usage,
it will cause a subscribe-dialog-usage (for the refer event package) to
be established in the dialog as well.
These two usages terminate *independently* of one another. The
invite-dialog-usage will probably end with a BYE when the transfer
succeeds. But the subscribe-dialog-usage, and hence the dialog, remains
until you terminate it, with the appropriate NOTIFY message.
In principle you can send a subscribe within an dialog established by an
INVITE. (This is done by some implementations.) And its conceivable to
send an INVITE within a dialog established by a SUBSCRIBE, though I have
never heard of it being done. These sorts of usage have been deprecated,
because they introduce some nasty error situations.
Thanks,
Paul
> I know I am asking the basics but it will improve my understanding.
>
> Thanks.
>
> On Tue, Apr 26, 2011 at 8:55 PM, Worley, Dale R
> (Dale)<dwor...@avaya.com>wrote:
>
>> Although it is not mentioned in any of the RFCs, the universal way of using
>> REFER for call transfer is to send the REFER within the dialog that you are
>> transferring, the dialog that was created by the initial INVITE. "Out of
>> dialog REFER" is rarely used for call transfer.
>>
>> It is very uncommon to have a subscription and an "INVITE dialog usage"
>> (that is, phone call) within the same dialog -- with the exception of the
>> subscription that is created by a REFER within the INVITE dialog usage.
>>
>> Dale
>>
> _______________________________________________
> Sip-implementors mailing list
> Sip-implementors@lists.cs.columbia.edu
> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
>
_______________________________________________
Sip-implementors mailing list
Sip-implementors@lists.cs.columbia.edu
https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
