Connected Party ID (considered evil) Who I’m Talking To Cullen Jennings

Problem Basic problem is when A is talking to B, letting know A know that B has changed to C Can happen before or after 200 Can happen from caller to callee or callee to caller

Approaches 1) Consider this a update of state in dialog –1a) modify To/From (but tags stay same) –1b) put identity in some other header 2) Consider this a transfer to a new user

1a) Update To or From Pro: –Easy to understand and implement –Does not end up with duplicate data in some other location –Would make To and From meaningful Con: –Not compatible with 2543 Could use supported tag Harm when not understood is minimal –(Will get a 481) Number of 2543 endpoints is dropping

1b) Update with new header Could put identity in new header, body, AIB – (but not PAI) Pro: –Backward compatible 2543 –same end result as 1a Con: –Phones display one thing for identity. SIP has To/From, PAI, SMIME cert identity, identity identity, Contact, Headers in AIB, and now something else? What does a UA developer display on phone?

2) Consider it a transfer Pro: –We have it. –Consistent use of protocol for when B changed to C Con: –Early attended transfer has issues –Transfer has some serious security issues if S/MIME & AIB is not used. May be disabled across trust domains.