Subject: Re: [Roll] AD review of draft-ietf-roll-minrank-hysteresis-of-04

From: Omprakash Gnawali <[email-masked]>
Date: Tue, 15 Nov 2011 14:39:58 -0600

Adrian, thanks for the feedback. I have incorporated some of your
comments, but there are some items I wanted to run by you before
posting a new version:

...

>
> In progressing the OG0 draft we learnt that there was no clear
> understanding of what an objective function is. I think your draft does
> a good job at explaining, but in an attempt to learn from the past, can
> you please have a look at the text that got added to the OF0 document to
> see whether anything can be added here.

I looked through both the drafts and also rpl draft. I could mention
the relevant sections of RPL draft in the first sentence of section 1:

An objective function specifies how RPL [I-D.ietf-roll-rpl] selects
   paths.

to:

An objective function describes how RPL [I-D.ietf-roll-rpl] selects
   paths within the role defined in Section 3.2.1 and using the
   guidelines listed in Section 14 of [I-D.ietf-roll-rpl].

Isn't that better than every OF draft describing what an OF is and
what it is supposed to do?

> ---
>
> Why is "Minimum Rank Objective Function with Hysteresis" MRHOF not
> MROFH?

We can change the name to Minimum Rank Hysteresis Objective Function.

>
> ---
>
> During the review process for OF0 we ended up adding the following
> paragraph. Would you consider adding something similar to make this
> point crystal clear?
>
>   The RPL specification [I-D.ietf-roll-rpl] requires the use of a
>   common OF by all nodes in a network.  The possible use of multiple
>   OFs with a single network is for further study.

Do you prefer to repeat this in each OF draft, even though it is
already mentioned in rpl draft?

...

> Section 5.1
>
> Can you add a statement on default values?

Here is the current statement on default values:

The parameter values are assigned depending on the selected metric.
   The best values for these parameters should be experimentally
   determined.  The working group has long experience routing with the
   ETX metric.  Based on those experiences, these values are
   RECOMMENDED:

If you think it would be better to clarify some aspect of the above
statement or something
additional, I am happy to add those statements. I will put the above statement
and the table of default values as a separate subsection (5.1) and manageability
will become 5.2.

>
> Can you also have a look at Section 7 of the OF0 draft. This gives a
> more substantive approach to describing manageability.

How about changing:

   The parameters MAX_LINK_METRIC, MAX_PATH_COST, MIN_PATH_COST,
   PARENT_SWITCH_THRESHOLD, PARENT_SET_SIZE, and ALLOW_FLOATING_ROOT
   should be configurable.

to

   Out of the box, the parameters MAX_LINK_METRIC, MAX_PATH_COST, MIN_PATH_COST,
   PARENT_SWITCH_THRESHOLD, PARENT_SET_SIZE, and ALLOW_FLOATING_ROOT
   should be set to the default values. The default value MAY be
different from the ones
   described in Section 5.1. These values may be further modified
using guidelines in Section 16
   of [I-D.ietf-roll-rpl].

- om_p