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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.