Subject: Gen-ART Telechat review of draft-ietf-v6ops-ipv6-roaming-analysis-06

From: "Peter Yee" <[email-masked]>
Date: Tue, 14 Oct 2014 23:53:42 -0700

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 wait for direction from your document shepherd or AD before posting a
new version of the draft.

Document: draft-ietf-v6ops-ipv6-roaming-analysis-06
Reviewer: Peter Yee
Review Date: October-14-2014
IETF LC End Date: September-29-2014
IESG Telechat date: October-16-2014

Summary: This draft is ready with issues for publication as an Informational
RFC. [Ready with issues]

This draft discusses some of the issues that may occur when a mobile device
roams on a visited network and attempts to use IPv6.  The technical meat of
the draft is fine, but the language usage makes it difficult to read through
without extra effort and reflection.  I'm not a 3GPP expert by any stretch
of the imagination, so I can't tell if the analysis made is sufficiently
comprehensive, but it appears to cover all of the IPv4/IPv6 combinations and
home/local breakout uses cases.

The following corrections appeared in my -05 review and have not been
addressed.  I have not updated the page numbers to match any border cases
that might have moved one way or another, but the section numbers should be
correct.

Minor issues: 

General: 

There are a lot of definite (the) and indefinite articles (a/an) missing in
the draft.  This makes it really difficult to read and interpret what is
meant.  In some cases, the plural form would also make sense, so it's hard
to know how to interpret the sentence.  I hate to say it, but please look
carefully at pretty much any acronym/initialism and the common nouns.  Make
a determination if an article is appropriate.  I started to mark these items
in the document while doing my review but became bogged down by the sheer
number of missing and in a few cases superfluous articles.  I do understand
that English may not be a primary language for several of the authors and
appreciate your indulgence in trying to make the document more readable and
therefore more useful.

Nits:

General: 

Separate references from the preceding text with a space, again for
readability.

I'll leave the Oxford/Harvard/serial comma alone for this review -- the
first general nit will take enough time to straighten out!

Specific:

Page 3, 4th bullet item, 2nd sentence: omit the commas.

Page 10, Section 4.2, 2nd paragraph, 2nd sentence: I don't think the word
risky is what you mean.  More like guaranteed, right?

Page 12, Section 5.2, 3rd paragraph, 1st sentence: change "to" to "on".

Page 12, Section 5.2, 3rd paragraph, 1st sentence: insert "the" before
"local".

Page 12, Section 5.2, 4th paragraph, 1st sentence: delete "the" before
"local".  (This correction was misapplied to paragraph 3 in the -06 draft,
so I'm fixing it with the previous nit and leaving this one in place.)

Page 14, Section 7, 2nd paragraph, 4th sentence: I'm simply having troubles
parsing this sentence.  Please rewrite for clarity.  (Sorry, this one is
still an issue.)

Page 15, 2nd bullet item, 2nd sentence: insert "a" before "AAA".

---

From: Jari Arkko <[email-masked]>
Date: Wed, 15 Oct 2014 20:52:48 -0700

Peter: Thank you for the detailed review.

(FWIW, I have not done a full review of -06, but I did read enough of it to get an understanding of how easy or difficult it is to read. It is not the easiest read, but I think quite reasonable for the given topic. Some of the complexities are inherent in having to explain the different roaming situations and arrangements.)

I plan to ballot no-objection for tomorrow’s IESG review. Finally, I’d like to thank the authors for writing the document on this important topic.

Jari

---

From: GangChen <[email-masked]>
Date: Thu, 16 Oct 2014 23:58:33 +0800

Hi Peter,

Many thanks for the review.
I will incorporate your comments in the next update.
I reply the comments inline for your further check.
> Page 3, 4th bullet item, 2nd sentence: omit the commas.

Ack

> risky is what you mean.  More like guaranteed, right?

I guess "risky" is intended to say. If the home operator performs roaming
steering targeted to an operator that doesn't allow IPv6, IPv6-only visitors
couldn't be guaranteed to get the IPv6 address.

> Page 12, Section 5.2, 3rd paragraph, 1st sentence: change "to" to "on".

Ack

> Page 12, Section 5.2, 3rd paragraph, 1st sentence: insert "the" before

Ack

> so I'm fixing it with the previous nit and leaving this one in place.)

Ack

> parsing this sentence.  Please rewrite for clarity.  (Sorry, this one is

The 3rd paragraph in Section 3 has detailed analysis on the issue.
I rewrite the sentence as below. Please kindly check if the sentence
is acceptable.

==OLD Text==

   That PDP/PDN type is
   supported in new-built EPS network, but isn't supported well in the
   third generation network.  The situations may cause the roaming
   issues of declining the attach request of dual-stack subscribers.

==NEW Text==

   That PDP/PDN type is
   supported in new-built EPS network, but isn't supported well in the
   third generation network. Visited SGSNs may discard the subscriber's
   attach requests because the SGSN is unable to correctly process
   PDP/PDN type IPv4v6.

> Page 15, 2nd bullet item, 2nd sentence: insert "a" before "AAA".

Ack

BRs

Gang