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. 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. 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.) 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? Nits/editorial comments: * You use a lot of domain-specific acronyms in section 1 before saying what they mean in section 2. * 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. * Section 2: (I'm no fun) Do you want this alternate expansion of FGL to stand? * Figure 2: the left table has a VLAN of 4095, which is inconsistent with the prose. * 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. * 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.