16 aug 2012 kl. 16:43 skrev Iñaki Baz Castillo:

> Thanks to both. It's clear. I had some doubts since RFC 3265
> (obsoleted by 6665) allows multiple subscription dialog creation if a
> proxy forks a SUBSCRIBE. But those dialogs are created in the UAC upon
> receipt of each NOTIFY with different From-tag (rather than creating
> the dialog upon the receipt of the *single* 200 OK for the initial
> SUBSCRIBE).
> 
> Thanks.
> 
> 
> 2012/8/16 Brett Tate <[email protected]>:
>>> Hi, if a UAC sends a SUBSCRIBE and the proxy does parallel forking to
>>> two servers, it could occur that both servers reply a 200.
>>> 
>>> Should the proxy relay the second 200 to the UAC? or should it absorb
>>> it?
>> 
>> It should be consumed instead of relayed by the proxy.
>> 
>> RFC 3261:
>> 
>> "This step, combined with the next, ensures that a stateful
>> proxy will forward exactly one final response to a non-INVITE
>> request, and either exactly one non-2xx response or one or more
>> 2xx responses to an INVITE request."
>> 
>> RFC 6026:
>> 
>> "When receiving any SIP response, a transaction-stateful proxy MUST
>> compare the transaction identifier in that response against its
>> existing transaction state machines.  The proxy MUST NOT forward the
>> response if there is no matching transaction state machine."
> 

This is actually a good test scenario. 

I guess the UAC wants to send a Subscribe with Expiry:0 on the second dialog to
terminate it.

/O
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