Karl, I agree with your comments on CallID being preserved when calls are transferred. However...

As an alternative, we might add a new multilevel CallID (e.g. to H.225.0 v3) that consists of an identifier that indicates the "overal call" and a second identifier that indicates the call leg.

Isn't this the CRV, that's always been there? Regards, Chris -- Dr Chris Purvis - Senior Development Engineer, WAVE CC Software Madge Networks Ltd, Wexham Springs, Framewood Road, Wexham, Berks. Phone:+44 1753 661359 email: cpurvis@madge.com