July 28, 2009
BLISS WG IETF-75
4
Open Issue: Replaces and Join
• "User Agents SHOULD support sending and receiving an INVITE with a
•  Replaces [RFC3891] header to allow the Call Pickup operation.  User
•  Agents SHOULD support sending an INVITE with a Join [RFC3911] header
•  field to initiate bridging.  UAs SHOULD either support receiving a
•  Join header field or be configured to use a conference server or
•  B2BUA which supports the Join header field.
•
•     OPEN ISSUE: Replaces and Join support is a SHOULD.  This means
•     that taking and bridging/joining calls could fail if the UA does
•     not support them.  Can we make these a MUST so that we can avoid
•     these failures?”
•Proposal:  Make Replaces and Join MUST for system - if a UA does not support accepting, a B2BUA could implement on behalf.