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

Request Review of draft-ietf-lsr-flex-algo
Requested rev. no specific revision (document currently at 13)
Type Last Call Review
Team Routing Area Directorate (rtgdir)
Deadline 2020-10-16
Requested 2020-10-01
Requested by Acee Lindem
Authors Peter Psenak, Shraddha Hegde, Clarence Filsfils, Ketan Talaulikar, Arkadiy Gulko
Draft last updated 2020-10-18
Completed reviews Rtgdir Last Call review of -12 by Eric Gray (diff)
Comments
Last request was for early review. Please cancel previous.
Assignment Reviewer Eric Gray 
State Completed
Review review-ietf-lsr-flex-algo-12-rtgdir-lc-gray-2020-10-18
Posted at https://mailarchive.ietf.org/arch/msg/rtg-dir/U2-eorpvdIZiFTeOmkDKNnGyHQM/
Reviewed rev. 12 (document currently at 13)
Review result Has Nits
Review completed: 2020-10-16

Review
review-ietf-lsr-flex-algo-12-rtgdir-lc-gray-2020-10-18

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