Issue 2: caller prefs param? Currently, instance ID is a callee capability parameter Implication: can use it in Accept or Reject Contact header fields Would allow routing to instance ID without GRUU, sort of Caller prefs routing not reliable, no guarantees This is part of reason why original instance approach for transfer was rejected in favor of GRUU Proposal Keep as callee cap (it IS a characteristic) Add text advising strongly against usage with Accept/Reject contact – use a GRUU instead |