As we can see from your discussion, it seems that 405 is awkward to use
and
can lead to confusion.
I think I still favour 403 Forbidden.
To make it more helpful, one could add a Reason header:
Reason: SIP ;cause=403 ;text="Method Not Allowed for Subscription
Dialog"
Thanks for your responses.
Regards,
Attila
-----Original Message-----
From: [email protected] [mailto:[email protected]]
Sent: 16 April 2009 11:15
To: Attila Sipos
Cc: [email protected]
Subject: RE: [Sip-implementors] BYE after SUBSCRIBE?
Now we can think of two scenarios,
1)A subscription within a Invite tansaction.
2)A subscription outside a invite transaction.
In the second scenario,sending a 405 without including BYE in allowed
methods will not be a problem,since we do not want to use a BYE within a
subscription dialogue.
In case we need to start a invite transaction then we can send another
message with BYE included in the allowed header.
However in the first scenario,we cannot send a 405 with BYE not included
in the Allowed header field as this will confuse the invite transaction.
A 403 will be fine but it will not allow the UAC to debug the error.
One solution I can think of is sending a 486 busy here with a
retry-after field set equal to the subscription interval, This will
ensure that the UAC does not re-transmit the BYE within this period,and
at the expiration of the timer the notifier will anyway send out a
subscription temination.
But then this is a crooked and dis-graceful way.
I cannot think of any other solution which will be both graceful and
effective.
Another solution as I mentioned in my first mail will be to send a 481
and to terminate the transaction at the notifier end to stop
transmission of the subscription termination.
Let me know your thoughts.
Thanks and regards,
Shamik Saha
Project Engineer
Voice Protocols
Cell : +91-9886704155
-----Original Message-----
From: Attila Sipos [mailto:[email protected]]
Sent: Thursday, April 16, 2009 3:14 PM
To: Shamik Saha (WT01 - Telecom Equipment)
Cc: [email protected]
Subject: RE: [Sip-implementors] BYE after SUBSCRIBE?
Thanks for the responses.
Shamik, I undestand your reasoning - but what would be the contents of
the Allowed header in the 405 response?
And if the Allowed header only lists SUBSCRIBE, wouldn't it imply that
that INVITE, BYE, etc aren't supported? So, it could confuse something
receiving that response.
Or if the Allowed header listed all methods as usual, it wouldn't help
work out the problem and would be in contradiction to the meaning of the
405 response.
Maybe "403 Forbidden" would be better though it doesn't help work out
why the request went wrong. It does seem to be a more accurate reason
than 405.
21.4.4 403 Forbidden
The server understood the request, but is refusing to fulfill it.
Authorization will not help, and the request SHOULD NOT be repeated.
Regards,
Attila
-----Original Message-----
From: [email protected] [mailto:[email protected]]
Sent: 16 April 2009 08:37
To: Attila Sipos
Cc: [email protected]
Subject: RE: [Sip-implementors] BYE after SUBSCRIBE?
A problem with 481 can be that the subscriber receiving 481 will
consider the dialog as terminated,but the notifier will retain the
dialog state.
Eventually the notifier will terminate the dialog on timeout and send a
subscription terminated message to the subsciber.
The subsciber on receiving this message will try to match a existing
subscirption which it will nt find as the subscirption has already being
terminated on its end and so it will send a 481 subscription does not
exist.
Thus this scenario will lead to a dis-graceful subscription termination
with extra messaging overhead.
One solution can be the notifier terminating the dialog at its end also
before sending the 481 response,so that it need not send any more
subscription terminated message,but still that will be a dis-graceful
termination,other than that I think 405 is still a good option.
Thanks and regards,
Shamik Saha
Project Engineer
Voice Protocols
Cell : +91-9886704155
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of
Attila Sipos
Sent: Thursday, April 16, 2009 12:25 PM
To: [email protected]
Subject: [Sip-implementors] BYE after SUBSCRIBE?
As we know, when a new SUBSCRIBE occurs, it creates a dialog.
But what should one do when a BYE is received on a SUBSCRIBE dialog?
I don't think "405 Method Not Allowed" is right but maybe "481"?
I can't believe that BYE should clear the dialog because, IMO, BYE is
only valid for INVITE-created dialogs.
Regards,
Attila
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