Hi Anish:
If a proxy on the path is a forking-proxy and it forked the request. In this
case the unanswered branches will be cancelled by the proxy using a CANCEL,
and this CANCEL will lead to a 487 to be generated on that particular
branch.
<snip rfc=3261 section=16.10>
Section 8.2. Furthermore, the element MUST generate CANCEL requests
for all pending client transactions in the context as described in
Section 16.7 step 10.
/<snip rfc=3261 section=16.10>
<snip rfc=3261 section=16.7>
10. Generate CANCELs
If the forwarded response was a final response, the proxy MUST
generate a CANCEL request for all pending client transactions
associated with this response context.
</snip rfc=3261 section=16.7>
So this is the case when UA or an Expires header doesn't play any role in
the CANCEL. So the 487 generated for the cancelled INVITE transaction (for
which a final response had not yet been generated). Having said that, since
4xx is a hop-by-hop response, I am not sure (maybe someone can confirm),
whether a stateful proxy is supposed to "consume" it.
my 2 cents,
Banibrata Dutta
--
On 12/13/05, Anish. T. George <[EMAIL PROTECTED]> wrote:
>
> Hi ,
>
> i would like to know that, Is there any Scenarios for which,
> an invite can be responded with 487 "Request Cancelled".. ??
>
> As my understanding, 487 can be received when the request is cancelled
> with
> "CANCEL"
> or invite requests expires if Expires header is present in INVITE request.
>
> If i havnt added an Expires header and i dint cancell the request,
> Is there any other scenario where i can get 487 for an INVITE request ??
>
> looking forward for your valuable comments..
>
> Thanks & rgds
> Anish .T. George
> Openera Technologies Pvt Ltd.
>
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