Hi Christer The caller identity blocking could be offered as a supplementary service - something like Enhanced Incoming Communication Barring. The users can subscribe to this just as they subscribe to any other service. So as part of this service execution, the proxy or CSCF needs to look for the Reason header in the incoming CANCEL or BYE requests and if found should pick the mentioned identity and add the identity to the user's black list. Now say based on this service Alice blocks Bob and the proxy parses the BYE message with Reason header, then the proxy adds Bob's identity to Alice's black list. Now when Bob calls Alice, then Proxy looks into Alice's black list and since Bob's identity is present, sends a 4xx (e.g blocked user) response to Bob indicating that Alice blocked Bob. In the CR I submitted to 22.173 for enhanced ICB, I mentioned that the Proxy or server can store details like Actual Identity, Published Identity, Reason for block, duration of block for a particular user. Now these details can be standardized as part of a event package and then can be used to notify the users of blocked calls using SUBCRIBE / NOTIFY procedures and XCAP. Regards Ranjit -----Original Message----- From: sipping-bounces@xxxxxxxx [mailto:sipping-bounces@xxxxxxxx] On Behalf Of Christer Holmberg Sent: Tuesday, March 03, 2009 1:53 PM To: Victor Pascual Ávila; Hadriel Kaplan Cc: sipping@xxxxxxxx Subject: Re: New Internet Draft for Caller Identity Blocking Hi, >>Some other comments on your draft: >>1) You show the Reason header being removed by the Proxy. While that may make sense for some cases, for being out on vacation it does not - I *want* the UAC to see it. > >I believe the header can reveal sensitive information for an attacker: >permanent blocking vs temporal blocking (and the expires). How does I know that there will be a proxy that supports the extension in the first place, and that would remove the header from the CAN/BYE/4xx? If no proxy supports the extension the Reason header may be passed all the way to the UAC... Regards, Christer _______________________________________________ Sipping mailing list https://www.ietf.org/mailman/listinfo/sipping This list is for NEW development of the application of SIP Use sip-implementors@xxxxxxxxxxxxxxx for questions on current sip Use sip@xxxxxxxx for new developments of core SIP _______________________________________________ Sipping mailing list https://www.ietf.org/mailman/listinfo/sipping This list is for NEW development of the application of SIP Use sip-implementors@xxxxxxxxxxxxxxx for questions on current sip Use sip@xxxxxxxx for new developments of core SIP
