Jari - Thanx for the comments. Inline. > -----Original Message----- > From: Jari Arkko [mailto:jari.arkko@xxxxxxxxx] > Sent: Thursday, November 19, 2015 2:58 AM > To: Les Ginsberg (ginsberg) > Cc: Robert Sparks; General Area Review Team; draft-ietf-isis-route- > preference.all@xxxxxxxx; ietf@xxxxxxxx; isis-wg@xxxxxxxx > Subject: Re: [Gen-art] Gen-art LC review: draft-ietf-isis-route-preference-02 > > Thanks for the review, Robert. > > Robert's question was good, and your answer Les was spot. What I'm > wondering is whether it would be useful to add something to the document > about your answer, Les? Or at the very least, a reference to Appendix A from > Section 2. And if you add something about transition mechanisms, it could > simply be "... transition mechanisms (such as configuration setting) ...". > [Les:] The devil is really in the details in this draft - and I appreciate if you are not heavily into the protocol details things can be easily misinterpreted. The draft makes one non-backwards compatible change to the protocol - which is to eliminate the incorrect " Level 2 down prefix" route type defined in RFC 5308. This is the change that could require a transition mechanism. Appendix A documents a real world interoperability issue - but it is NOT directly related to RFC 5308. It results from inconsistent interpretation of content in RFC 5302/RFC 5305. There is no transition mechanism proposed for this as the incompatibility already exists in some deployments. What is needed here is for the non-conforming implementations to correct their behavior. We could mention Appendix A in Section 2 - but it would NOT be related to the transition mechanism which is suggested in that section. (Hope this makes sense) Les > Jari > > On 27 Oct 2015, at 21:41, Les Ginsberg (ginsberg) <ginsberg@xxxxxxxxx> > wrote: > > > Robert - > > > > Thanx for the review. > > Responses inline. > > > >> -----Original Message----- > >> From: Robert Sparks [mailto:rjsparks@xxxxxxxxxxx] > >> Sent: Tuesday, October 27, 2015 12:14 PM > >> To: General Area Review Team; > >> draft-ietf-isis-route-preference.all@xxxxxxxx; > >> ietf@xxxxxxxx; isis-wg@xxxxxxxx > >> Subject: Gen-art LC review: draft-ietf-isis-route-preference-02 > >> > >> I am the assigned Gen-ART reviewer for this draft. The General Area > >> Review Team (Gen-ART) reviews all IETF documents being processed by > >> the IESG for the IETF Chair. Please treat these comments just like > >> any other last call comments. > >> > >> For more information, please see the FAQ at > >> > >> <http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq>. > >> > >> Document: draft-ietf-isis-route-preference > >> Reviewer: Robert Sparks > >> Review Date: 27Oct2015 > >> IETF LC End Date: 30Oct2015 > >> IESG Telechat date: Not yet scheduled > >> > >> Summary: Ready for publication as Proposed Standard > >> > >> This document reads easily despite most of it being detailed lists. I > >> have no objection to it moving forward, but I would like to check one > thing: > >> > >> The sparsity of detail at the end of section 2, where you call out > >> potential interoperability issues and suggest that "implementers may > >> wish to support transition mechanisms" is concerning. It might be > >> worth being explicit here about the interoperability issues, and what > >> a transition mechanism might look like, particularly if there's a > >> chance of having to deal with a peer that won't implement what's > described in this draft? > >> > > [Les:] Appendix A provides a real-life example of how the interoperability > issue manifests itself. As far as how a transition mechanism might be > implemented this gets into non-normative aspects. I have always had a > strong bias for avoiding non-normative statements in specifications. > Transition here really means having some configuration knob to specify > whether old/new behavior should be used. Specifying a CLI is not something > I would want to put into a standard. For folks who have an IS-IS > implementation it isn't difficult to figure out how to do this. > > > >> Did the group consider defining a couple of new code points and > >> deprecating these two, to avoid that transition issue? > > > > [Les:] This would not help - it would only make things more difficult. You > would then have to deal with the transition between the old TLV and the > new TLV - which has a much broader impact because it affects all IPv6 prefix > reachability advertisements in all deployments - whereas the existing > problem only occurs in certain deployments (multiple instances of IS-IS on > the same router with redistribution between the instances at Level-2). > > > > Les > > > > _______________________________________________ > > Gen-art mailing list > > Gen-art@xxxxxxxx > > https://www.ietf.org/mailman/listinfo/gen-art