Last Call Review of draft-allan-5g-fmc-encapsulation-04
review-allan-5g-fmc-encapsulation-04-tsvart-lc-black-2020-06-30-00

This document has been reviewed as part of the transport area review team's
ongoing effort to review key IETF documents. These comments were written
primarily for the transport area directors, but are copied to the document's
authors and WG to allow them to address any issues raised and also to the IETF
discussion list for information.

When done at the time of IETF Last Call, the authors should consider this
review as part of the last-call comments they receive. Please always CC
tsv-art@ietf.org if you reply to or forward this review.

This is well-written concise draft that defines a PPPoE encapsulation for
carrying data between a 5G residential gateway and the associated 5G Access
Gateway Function (AGF).  For reasons described in the draft, it addresses that
scenario well.

I have one minor concern with this draft, which is almost a nit.  The draft
should have a stronger statement of applicability to indicate that the
encapsulation applies only to the specific 5G usage envisioned, as that usage
relies upon the network operator provisioning sufficient bandwidth and managing
the network accordingly.  This encapsulation is not suitable for deployment
over the public Internet in general or any network in which congestion is an
important operational consideration.  This is because the encapsulation may
carry non-congestion-responsive traffic, as further indicated by specific QFI
values.  A detailed discussion of congestion is not necessary - clarification
and focus of applicability of the encapsulation should suffice.