Shepherd writeup

1. Summary

Document shepherd: Simon Perreault <>
Responsible Area Director: Spencer Dawkins <>

The intent of this document is to define a mechanism for TURN allocations to
survive a client IP address change. A new "mobility ticket" attribute allows the
client to migrate to a new IP address using a make-before-break approach.

The requested publication type is Proposed Standard because new TURN attributes
and behaviour are defined.

2. Review and Consensus

The draft was discussed actively in the MMUSIC working group, under the name
MICE, before it was refocused and transferred to TRAM. Once in TRAM there were
few iterations: the WG was roughly happy with the document as it was. A few good
reviews were done by core WG members which resulted in small changes.

Interest in this document has been medium. The mechanism for TURN makes sense
but there are a number of other layers in a SIP/WebRTC stack at which IP address
mobility could be implemented, e.g., trickle ICE, re-INVITE, etc. At this moment
there is no single agreed-upon "how IP address mobility shall be accomplished"
vision and implementations have not yet picked a clear winner. Since the draft
was first proposed in MMUSIC a sort of "wait and see" response had been slowing
progress.  Today it seems like there won't be a clear decision and the consensus
is that publishing the TURN mechanism is what makes most sense at this point.

3. Intellectual Property

Each author has stated that their direct, personal knowledge of any IPR related
to this document has already been disclosed, in conformance with BCPs 78 and 79.
There was no IPR disclosure.

4. Other Points

This document makes two IANA registrations in existing registries. Both are
clear and require IETF Review.