Hi Robert, A version -05 has been uploaded with the intent that it resolve your comments. Thanks, Donald =============================== Donald E. Eastlake 3rd +1-508-333-2270 (cell) 155 Beaver Street, Milford, MA 01757 USA d3e3e3@xxxxxxxxx On Wed, Jun 29, 2016 at 4:09 PM, Donald Eastlake <d3e3e3@xxxxxxxxx> wrote: > Hi Robert, > > Thanks for your thorough comments. See below. > > On Tue, Jun 28, 2016 at 3:33 PM, Robert Sparks <rjsparks@xxxxxxxxxxx> > wrote: >> 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-trill-tree-selection-04 >> Reviewer: Robert Sparks >> Review Date: 28 Jun 2016 >> IETF LC End Date: 1 Jul 2016 >> IESG Telechat date: 7 Jul 2016 >> >> Summary: Ready (with nits) for publication as Proposed Standard >> >> This document is easy to read, even for someone not deeply steeped >> in trill. >> >> I have a few questions and suggestions to consider >> >> 1) The essence of the idea this document provides support for is that an >> operator will create and install a configuration that meets the one tree per >> identifiable thing (such as VLAN) constraint. > > Well, it helps as long as multi-destination traffic identified by VLAN > or whatever is carried by fewer than all trees. It need not be one. > >> The protocol proposed here >> does not try to enforce that the operator supplies a configuration meeting >> that constraint. Should the things that generate messages with the TLVs >> defined in this document be restricted from sending messages that would map >> the same VLAN to two trees? I understand things will still work >> (suboptimally, as pointed out in the backwards-compatibility section), but >> it seems this configuration error should be mitigated. Section 3.3 also >> pulls the punch a little with it's discussion at the end of the second >> paragraph. If you're going to leave it up to the unspecified way the >> operator installs this configuration, you might at least point out that this >> is something to look for and complain about. If you think the optimal >> configuration isn't a likely thing to reach, then consider a pass through >> the document that sets that expectation consistently. > > While restricting, for example, VLAN-x to one tree is optimal from the > point of view of using up the least amount of fast path FIB > (Forwarding Information Base) resources in some hardware > implementations, it is not optimal from the point of view of load > spreading. To get optimal load spreading, you would want to spread > different multi-destination flows onto different distribution trees. > >> 2) There are a couple of places where you use 2119 where you appear to be >> restating requirements from other documents. That's dangerous, from a >> document set maintenance point of view. Please consider changing these to >> simple prose, leaving the 2119 requirements to the protocol you're defining >> in this document. Please look at the SHOULD in the Background Description, >> and the SHOULD NOT in the first paragraph of the Overview. (2119 in sections >> like backgrounds and overviews is usually a sign that somethings in the >> wrong place.) > > The SHOULD in the Background Description is indeed just echoing the > same provision from [RFC6325] and can be changed to not use a 2119 keyword. > > The SHOULD NOT in the first paragraph of the Overview (Section 3.1) is > entirely due to theis draft and not inhereted from any other document. > >> 3) In the 3rd paragraph of 3.3, why is the requirement SHOULD strength? What >> else would the RBridge do, and when would it be reasonable for it to do that >> something else? > > The "SHOULD" requirement is to use a tree that the choosing RBridge > has advertised it will use; however, it is not actually required to > advertise which tree(s) it will use. Furthermore, even if it has, that > tree(s) might just have become unavailable due to one or more > failures. We can probably add some words to clarify that. > >> Nits/editorial comments: >> >> * You use a lot of domain-specific acronyms in section 1 before saying what >> they mean in section 2. > > Looks to me like the terminology section could be moved up. > >> * The first sentence in the 8th paragraph of 1.2 is very >> complex. (It's the one that starts "In cases where blocks >> of"). Please consider simplifying it. > > I think it can be re-worded. > >> * Section 2: (I'm no fun) Do you want this alternate expansion of >> FGL to stand? > > Nope... Looks like a global replace run amok or something, that should > be fixed :-) > >> * Figure 2: the left table has a VLAN of 4095, which is inconsistent >> with the prose. > > Shold be fixed. 4095 (0xFFF) is not a valid VLAN ID. > >> * In section 3.4 you use 2119 RECOMMENDED (which is equivalent to >> SHOULD) when describing how the operator configures things. This >> isn't a constraint on the protocol defined in this document. Please >> consider rewriting the sentence without the 2119 keyword. > > Humm. I think those are good operational recommendations. We can try > changing "RECOMMEND" to "suggest" and see if we get push back to > change it back :-) > >> * Micronits: there's spurious space at the beginning of the 3rd line >> on page 6. There's an occurrence of BRridge that probably should >> have been RBridge in section 3.4, and "assigne" appears in the IANA >> Considerations. > > OK. > > Thanks, > Donald > =============================== > Donald E. Eastlake 3rd +1-508-333-2270 (cell) > 155 Beaver Street, Milford, MA 01757 USA > d3e3e3@xxxxxxxxx