I am an assigned INT directorate reviewer for draft-ietf-rtgwg-atn-bgp-12.txt. These comments were written primarily for the benefit of the Internet Area Directors. Document editors and shepherd(s) should treat these comments just like they would treat comments from any other IETF contributors and resolve them along with any other Last Call comments that have been received. For more details on the INT Directorate, see https://datatracker.ietf.org/group/intdir/about/ <https://datatracker.ietf.org/group/intdir/about/>.

This was a requested "early review" so not surprisingly needs some additional work before being done.

Technical Issues:
1) Section 3 explains that ASNs need not be coordinated with IANA since they're used in a separate BGP routing instance, but they still have to be unique within the ATN/IPS routing system.   However, no explanation is provided about how to ensure such uniqueness.   Who coordinates them then, to ensure that are unique?   In my view, this has to be solved before the document could be used.
2) Page 13 mentions that selection of a network-based s-ASBR could be done via any of several mechanisms, but there are no references provided and it seems that those mechanisms would require a specification as interoperability would be required.
3) Top of page 14 talks about "registering" addresses, but I couldn't tell what protocol it was referring to or where such addresses would be registered.  Clarify.
4) AERO and OMNI are listed as informative references but are used in text as if they are normative, not merely examples.   That is, as phrased the document seems to only be useful in an AERO/OMNI context.  Is it really specific to those or could other things (maybe RFC 5213 or whatever else) be used instead?  If the intent is to keep them as informative references, then either they should be used only as examples or they should be moved to be normative references.  Of course normative references from an IETF document to (currently) non-IETF drafts would be something that the RTGWG may want to carefully consider.

Editorial comments:
* Page 4 would be a lot easier to understand if there were a high level topology diagram there.
* See https://www.microsoft.com/en-us/research/uploads/prod/2017/05/draft-ietf-rtgwg-atn-bgp-12-DthalerReview.pdf for full review with above, and other editorial, comments in context.