Document: draft-ietf-idnabis-bidi-06.txt
     Right-to-left scripts for IDNA
Reviewer: Joel M. Halpern
Review Date: 5-Oct-2009
IETF LC End Date: 14-Oct-2009
IESG Telechat date: N/A

Summary: This document is nearly ready for publication as a proposed standard.
There is one comment I have marked as Major.  I presume that the actual problem is not a defect in the intent of the spec, but a defect in this readers understanding.  Presuming such, I would ask that clarifying text be added.

Major issues:
In section 2, when describing the rules for what is allowed in labels, CS is allowed in labels.  It is not allowed to start RTL labels.  This looks fine, until I realized that CS includes ".", which I am pretty sure is not allowed in a label.
This gets further complicated in section 3, when talking about "The Character Trouping requirement", the text talks about "Delimiterchars" 
being CS, WS, or ON.  A parenthetical then says "They are not allowed in domain labels."
Since the normative text said that CS is allowed, there seems to be a problem.

Minor issues:
Rule 6 in section 2 talks about the requirements on the termination of an LTR (left-to-right) label.  This requirement is much tighter than just "don't end with an RTL character", since rule 5 already said "don't use any RTL characters."
However, the non-normative introductory text says roughly that this document does not put constraints on labels which do not use RTL characters.
My guess, as a person who is neither a DNS expert nor a Unicode expert, is that rules 6 is not a new rule.
If rule 6 is equivalent to existing rules in other documents, shouldn't there be an explanation of the fact that it is a restatement of existing rules?  If it is not just a restatement, then how can you get away with it in this document?

At the end of section 2, there is a reference to LDH-labels.  That is the only occurrence of the string LDH in the document.  I presume it is a typo for something?