Subject: [manet] AD review of draft-ietf-manet-olsrv2-metrics-rationale

From: "Adrian Farrel" <[email-masked]>
Date: Fri, 14 Dec 2012 23:20:09 -0000

Hi,

I have done my usual AD review of your draft prior to issuing IETF
last call. The purpose of the review is to clear up any issues that
might arise during last call or IESG evaluation to save other reviewers
time, and to smooth the passage of the draft in those stages.

This document looks in pretty good shape to me. As a calibration, I
noted a number of questions as I went along, only to find you answered
them about half a page later. Thanks for all the work you must have put
in. 

I have a number of comments, but only the first two really need
attention. The others would be "nice to have".

If you can respin the document addressing these comments, I will issue
last call. As usual, all my comments are open for discussion.

Thanks,
Adrian

---

The punctuation and clause order in the Abstract is a little ambiguous.
The document does not "describe in order to allow routing". I have 
some suggested wording which I have rolled into my next point.

---

The document was clearly useful during the production of OLSRv2, and 
after discussion with the WG chairs I understand why the WG wants to
pursue publication even after all of the decisions have been made and
OLSRv2 accepted for publication.  However, the *current* purpose of the
document is not particularly clear so I have two suggestions:

In the Abstract add a few words as follows. I have also re-ordered the
clauses to cover my previous point.

   OLSRv2 includes the ability to assign metrics to links and to use 
   those metrics to allow routing by other than minimum hop count 
   routes.  This document provides a historic record of the rationale
   for and design considerations behind how link metrics were included
   in OLSRv2.

Add a new 3rd paragraph in Section 1

   During the development of OLSRv2 the working group and authors 
   repeatedly revisited discussion with others about how and why some
   choices were made in the protocol specification particularly at the
   metric integration level.  Some of the issues were non-intuitive 
   and this document is presented as a record of the considerations and
   decisions to provide informational discussion about motivation and 
   historic design choices.  This will be a useful reference document
   when those questions arise again.

The wording on these is not mandatory, but the inclusion of some sort 
of statement is going to make the document more useful and get it 
through the IESG more easily.

(BTW. Thank you for Section 3.)

---

Section 1 bullets

The use of "can use only" is a bit confusing. Suggest...

OLD
      routers can use only metrics of the physical type that they are
      configured to use.
NEW
      routers can be configured to use only a subset of the available
      metric types.
END

---

There is a mismatched double quote at symmetric link in the middle
paragraph.

---
                                                                              
I wonder whether you want to make any comments about node metrics.
Obviously, you don't have them (neighbor metrics being a different 
thing), but you could comment on why you don't have them (if this was
ever discussed).

The question is slightly touched on in 5.2 in discussion of "delay".

---

Section 8

Were there any security considerations that cropped up while designing
metric support in OSLRv2? If so, here would be the place to mention
them.

---

From: "Dearlove, Christopher (UK)" <[email-masked]>
Date: Mon, 17 Dec 2012 10:19:32 +0000

A quick comment to say, thanks for this Adrian, but I'm unlikely to get to this before the New Year (end of year deadlines, and we shut down next week).

In the meanwhile a Merry Christmas and Happy New Year to all who get this.

-- 
Christopher Dearlove
Senior Principal Engineer, Communications Group
Communications, Networks and Image Analysis Capability
BAE Systems Advanced Technology Centre
West Hanningfield Road, Great Baddow, Chelmsford, CM2 8HN, UK
Tel: +44 1245 242194 |  Fax: +44 1245 242124
[email-masked] | http://www.baesystems.com

BAE Systems (Operations) Limited
Registered Office: Warwick House, PO Box 87, Farnborough Aerospace Centre, Farnborough, Hants, GU14 6YU, UK
Registered in England & Wales No: 1996687

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of Adrian Farrel
Sent: 14 December 2012 23:20
To: [email-masked]
Cc: [email-masked]
Subject: [manet] AD review of draft-ietf-manet-olsrv2-metrics-rationale

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Hi,

Thanks,
Adrian

---

---

---

Section 1 bullets

OLD

---

---

---

Section 8

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