I'm the assigned reviewer of the DNS Directorate for this draft.
This document does not reference the DNS, and has no considerations
that reflect on the DNS.

The reviewer is not familiar with PASSporT and is not in a position to
make qualified comment on the topic.
That being said, this specification to add signed and integrity
protected rich call data is clearly motivated and the proposed
extension is clearly expressed.

A list of nits follows.

Page 5:
3 times: s/passport/PASSporT/

Page 13:
s/contraint/constraint/

Page 15:

   This document defines a new JSON Web Token claim for "crn", Call
   Reason, the value of which is a single string that can contains
   information as defined in

... that can contain


Page 20
s/consisent/consistent/

Page 22
s/PASSport/PASSporT/

Page 25
s/PASSport/PASSporT/

Page 26
s/cooresponding/corresponding/

Page 29
s/availbility/availability/