From: "Avasarala Ranjit-A20990" <[EMAIL PROTECTED]> Which is the appropriate 4xx message that can be used to inform user of an existing subscription?
As others have said, it's not an error, so there is no error response. Consider the following use case: User A sends a subscribe message with a particular event and gets subscribed to the service. Now at a later point of time the user is not sure if he has subscribed for a particular service or not. So he might send subscribe again. So is there a way to inform the user that the subscription for that service for the user already exists? That isn't quite the way to look at it. Given that NOTIFYs are always sent within a dialog, if the UA has truly forgotten about any possible subscription, it will have also forgotten the Call-Id of the dialog, and will have no context to recognize that an incoming NOTIFY is relevent to its subscription. So the old subscription must perforce be abandoned (and it will eventually time out), and the UA must create a new subscription. On the other hand, if the UA knows the Call-Id of a past subscription but doesn't know if the subscription is still valid, it can send a re-SUBSCRIBE, and the notifier will respond 200 (if it is still valid) or 481 (if not). Dale _______________________________________________ Sip mailing list https://www1.ietf.org/mailman/listinfo/sip This list is for NEW development of the core SIP Protocol Use [EMAIL PROTECTED] for questions on current sip Use [EMAIL PROTECTED] for new developments on the application of sip
