E.g. Scenario-1.2: Call-Trace with Number Privacy
Caller ID is masked in the From: field so that it is not displayed
Caller ID is stored in the P-Asserted-ID field for routing purposes (911, call trace), and other call features (block), etc.
INVITE From: “anonymous” sip:firstname.lastname@example.org P-Asserted-ID: “anonymous” tel:+2125551212 Privacy: id critical Proxy-Require: Privacy Off-hook CMS1 CMS2 MTA-1 MTA-2 Remainder of flow same as Scenario-1.1
Extension Matrix The choice of standard, private and future IETF SIP extension(s) for each service scenario can be largely debated. This is just an example, one view on how we meet requirements. This is where the difficulties of Inter-domain SIP arise in VoIP peering. 3-way Conference Visual MWI E911 Caller dials CIC & ported number Measured rate call E911 with Privacy Called number ported Carrier Selection – caller dials CIC Measured rate call Call-Trace with number privacy Flat-rate on-net call SIP carrier-to-PSTN Inter-carrier (trusted) Inter-carrier (non trusted) SIP Apps Intra-domain, Inter-Zone Extension Scenario Visual MWI Event Notify Replaces Header REFER UPDATE P-Asserted-ID P-DCS Tel-URI PRACK Pre-Conditions
Provide configuration means for end-users and/or providers to be capable of configuring the mandatory/optional SIP extensions advertised in the SIP signaling and provide means for enforcing SIP signaling “policies”