Subject: [Gen-art] Gen-ART review of draft-ietf-nfsv4-federated-fs-dns-srv-namespace-08

From: <[email-masked]>
Date: Fri, 23 Sep 2011 15:20:04 -0400

I am the assigned Gen-ART reviewer for this draft. For background on Gen-ART, please see the FAQ at <http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq>.

Please resolve these comments along with any other Last Call comments you may receive.

Document: draft-ietf-nfsv4-federated-fs-dns-srv-namespace-08
Reviewer: David L. Black
Review Date: September 23, 2011
IETF LC End Date: September 23, 2011

Summary: This draft is on the right track but has open issues, described in the review.

This draft specifies the use of DNS to locate the root of a federated filesystem namespace
based on the fs_locations functionality in NFSv4.

I have two significant open issues:

[1] There has been an extensive Last Call discussion of this draft, focusing on the use
of a composite two-component service name in DNS SRV records, and the apparent
incompatibility of that format with RFC 2782.  This discussion has surfaced a proposed
resolution in the form of  unitary single-level service name specified without a port
number.  It is *vital* that this proposed resolution be reviewed by DNS experts (probably
the DNS directorate) for consistency with DNS as currently specified and deployed.
Another IETF Last Call may be appropriate, as this change has a significant impact on
this draft, involving a serious rewrite of the portion of Section 4.2 that discusses the
possible use of more than two components in a service name and presents a three-component
example.

[2] While NFSv4.1 (RFC 5661) is restricted to TCP, this draft also references NFSv4.0
(RFC 3530) as applicable, and the latter is defined over both UDP and TCP.  Unfortunately,
this draft is written as if TCP is the only transport protocol for NFS - that's not the
case for NFSv4.0, so either this draft needs to say something about use with NFSv4.0 over
UDP, or needs to explicitly prohibit use of this DNS SRV record with NFS over UDP.  If
the former approach is pursued, RFC 5405 on Unicast UDP Usage Guidelines for Application
Designers is an important consideration in writing that text and RFC 5405 should be
added as an informative reference.

idnits 2.12.12 ran clean.

Thanks,
--David
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David L. Black, Distinguished Engineer
EMC Corporation, 176 South St., Hopkinton, MA  01748
+1 (508) 293-7953             FAX: +1 (508) 293-7786
[email-masked]        Mobile: +1 (978) 394-7754
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