I have reviewed this document as part of the Operational directorate's ongoing effort to review all IETF documents being processed by the IESG. These comments were written with the intent of improving the operational aspects of the IETF drafts. Comments that are not addressed in last call may be included in AD reviews during the IESG review.  Document editors and WG chairs should treat these comments just like any other last call comments.

This document specifies procedures for representing and verifying the application services identity in TLS interaction with PKI X.509 certificates.

I believe this document is well written and ready for publication. 

Major issue:
No

Minor issues:
1.Section 1.2 Applicability
s/ cetrificate/certificate

2. Delegated domain definition
“ For example, a server at mail.example.net could be a delegated domain for connecting to an IMAP server hosting an email address of user@example.net.
”
I can not parse this sentence, is the server a delegated domain? Which domain is the source domain? Which domain is delegated domain ? please make this clear in the example.
3.Section 2 Identifying Application Service
What is meaning difference between _direct_ and direct or _indirect_ and indirect? In section 2, sometimes _direct_/_indirect_ is used, sometimes direct/indirect is used.

4.Section 2 said:
“   We can categorize the three identifier types as follows:

   *  A DNS-ID is direct and unrestricted.

   *  An IP-ID is direct and unrestricted.

   *  An SRV-ID is typically indirect but can be direct, and is
      restricted.

   *  A URI-ID is direct and restricted.
”
Three identifier types or four identifier types? My impression is the latter.

5.Section 2
s/possibile/possible

6.Section 3 said:
“In this case, applications need
   to be aware that the textual representation of an IPv4 address can
   appear to be a valid DNS name, though it is not.  ”
it in the text ‘though it is not’ is referred to digit representation of an IPv4 address? Or not?

7.Section 7.1
I am surprised there is no protection measures to mitigate risk of vouching for rogue or buggy hosts in this document?