Summary: Has enough positions to pass.
I do have one comment, and it's only for consideration by the responsible AD. This document is great, and the shepherd thinks it's received sufficient review for publication as Informational, but I wonder if it might - make sense to publish as a BCP, which would generate additional review from other communities, OR - make sense to publish as Experimental, which might signal that this document is probably the right thing to, but the jury is still out, OR - include "You are not expected to understand this" in the Introduction, crediting Dennis Ritchie for prior art (*) I'm MOSTLY kidding ... (*) https://en.wikipedia.org/wiki/Lions%27_Commentary_on_UNIX_6th_Edition,_with_Source_Code#.22You_are_not_expected_to_understand_this.22
I think that this is a useful document -- I think that it would be more useful if it A: made DNS-SD be LDH only, or somehow made all DNS deployments be UTF-8 (without any sort of homograph issues), but seeing as both of these would require magic, I'm balloting Yes. :-) 2 nits: 1: ... "the so-called LDH rule" -- I think that it would be useful to expand this - the tone is introductory, and so I think helpful to new readers. 2: "cannot be used in the DNS unless they cleave to the LDH rule." - I would suggest "adhere to" or "follow" - 'cleave to', while cooler, is likely confusing to a: those who don't have English as a first language, or b: were born after 1886. :-)