Reviewer: Stewart Bryant
Review result: Ready
Firstly my apologies for the lateness of this review.
This is a very well written draft, and can proceed as is.
Useful clarity might be added to Section 4 (dataplane) by the inclusion of some
figures. I say this as someone that finds it easier to take in information in
that format, so that is a personal preference comment, the text is correct and
technically sufficient.
There is an intriguing piece of text in the dataplane section "While this may
be useful in certain scenarios, it may provide unintended results in other
scenarios." which I think might be usefully expanded to give at least one
example of a use, and an unintended consequence.
In the introduction it says: "In [RFC3107], this feature was controlled by a
BGP Capability Code that has never been implemented, and is now essentially
obsolete." which left me wondering whether there was the intention to formally
deprecate the feature through the RFC system.