Last Call Review of draft-ietf-lsr-flex-algo-12
review-ietf-lsr-flex-algo-12-rtgdir-lc-gray-2020-10-18-00

Hello,

I have been selected as the Routing Directorate reviewer for this draft. The
Routing Directorate seeks to review all routing or routing-related drafts as
they pass through IETF last call and IESG review, and sometimes on special
request. The purpose of the review is to provide assistance to the Routing ADs.
For more information about the Routing Directorate, please see
https://trac.tools.ietf.org/area/rtg/trac/wiki/RtgDir.

Although these comments are primarily for the use of the Routing ADs, it would
be helpful if you could consider them along with any other IETF Last Call
comments that you receive, and strive to resolve them through discussion or by
updating the draft.

Document: draft-ietf-lsr-flex-algo-12.txt

Reviewer: Eric Gray

Review Date: 16 October, 2020

IETF LC End Date: Unknown

Intended Status: Standards Track

Summary:

This document is well organized, relatively easy to read, and probably ready
for publication, but has one potential minor issue and a very small number of
NITs that might be considered prior to publication.

Major Issues:

None

Minor Issues:

The statement in section 15 (Backward Compatibility) - "This extension brings
no new backward compatibility issues" - seems somewhat flip.

I suspect that a tiny bit of analysis would not hurt.

The extensions in this draft are clearly intended to work in an environment
where routers that _do_not_ support these extensions are also deployed, but
apparently relies on configuration of those routers that _do_ support the
extensions to address this.

That seems correct.

From my reading of the draft (which I have not closely followed for its entire
development), while it introduces at least one new TLV, the OSPF routing
protocol has well defined handling for TLVs that are not understood - hence the
introduction of one or more new TLVs should not present a problem in OSPF.

Obviously Sub-TLVs of the new OSPF TLV type will not introduce compatibility
issues.

I assume (but do not actually know) that a similar situation exists for the new
ISIS FAD Sub-TLV of the existing TLV Type 242 - i.e. - ISIS presumably has well
defined handling for sub-TLVs (of at least type 242) that are not recognized. 
If so, than the new Sub-TLV types defined are also not an issue.

Shouldn't this section say something along these lines?  I suspect that it
would be more helpful if verifying the content of the "considerations" sections
were not left as an exercise for the reader.  😊

NITs:

In the Introduction, the phrase "must often be replaced" seems very slightly
problematic (especially given this is a standards track RFC wanna-be).  Would
it be better to say "is often replaced" instead?

In section 17.1.2 and 17.2 - '... a "Interior Gateway ...' should probably be
'... an "Interior Gateway ..." in both cases.

--

Eric