The E.164 to Uniform Resource Identifiers (URI) Dynamic Delegation Discovery System (DDDS) Application (ENUM)
RFC 6116

A number of acronyms are not expanded at their first occurance. For example: NS, NAPTR, SOA, FQDN (expanded in 3.1, but that is not the first occurance), ABNF, ITU-T TSB.

Please consider the issues brought up by Ari Keränen in his review:

1. Introduction

Abbreviations not opened (NAPTR, NS, SOA).

3.2.

    1.  Remove all characters with the exception of the digits.  For
        example, given the E.164 number "+44-20-7946-0148", this step
        would simply remove the leading '+', producing "442079460148".

Should say "[...] simply remove the leading '+' and all '-'"?

    2.  Reverse the order of the digits.  Example: "841064970244"
    3.  Put dots ('.') between each digit.  Example:
        "4.4.2.0.7.9.4.6.0.1.4.8"

The digits in step 3 should also be in the reversed order?


3.4.3. Services Parameters

        service-field = "E2U" 1*(servicespec)
        servicespec   = "+" enumservice
        enumservice   = type 0*(subtypespec)
        subtypespec   = ":" subtype
        type          = 1*32(ALPHA / DIGIT / "-")
        subtype       = 1*32(ALPHA / DIGIT / "-")

Missing ABNF reference. Is the lack of upper limit for number of 
servicespecs and substypespecs intentional?

minor comments...

I suggest adding a few words  explaining how this doc updates RFC3761, similar to the explanation in the IESG Writeup; e.g., "This document updates RFC3762 to reflect major operational issues discovered during deployment."

(mostly a curiosity question) The IESG Writeup notes that "RFC 3761 is in wide global deployment".  Have the updates in this document been widely deployed?  Have they caused any interoperability issues with deployments that have not been updated?

In section 3.2:

   In order to convert the AUS to a unique key in this database the
   string is converted into a domain name according to this algorithm:

   1.  Remove all characters with the exception of the digits.  For
       example, given the E.164 number "+44-20-7946-0148", this step
       would simply remove the leading '+', producing "442079460148".

Aren't the "-" characters also removed in this example?  I.e., "this step
would simply remove the leading '+' and internal '-' characters" ?