Re: [Efficientnd-dt] ND related test results draft

Hi Erik,

Please see in-line.

-----Original Message-----
From: Erik Nordmark [mailto:nordmark@sonic.net] 
Sent: Thursday, March 12, 2015 2:22 PM
To: Samita Chakrabarti; Erik Nordmark (nordmark@acm.org)
Cc: asood2@ncsu.edu; efficientnd-dt@ietf.org
Subject: Re: [Efficientnd-dt] ND related test results draft

On 3/9/15 4:18 PM, Samita Chakrabarti wrote:
>
> Hello Erik and all:
>
> A draft has been published by Ankur Sood (from North Carolina State 
> University); Ankur had done some simple tests with ND routers(linux 
> Ubuntu), a  non-intelligent Wifi access point which sends data back 
> and forth towards and from the wireless hosts ( two wifi phone devices 
> and a laptop ).
>
> The purpose of this draft is to see how RA messages can increase with 
> the frequency of interval and the difference between min and MAX 
> advinterval. Also how different sleeping host implementations behave 
> differently  around ND and DAD.
>
The part about the different behavior of of the hosts is quite informative. I think this is an area we should understand better to see how the implementation choices affect the network behavior.

[SC>]  Most importantly the sleepy behavior of the two wireless phones' implementations  and  anomaly in response to DAD messages. 

Changing maxRa and not minRa seems less useful than changing one and keeping the max:min ratio constant. One would expect that with a constant ratio between them the RA rate would be proportional to the timers. However, I can't easily check if that is the case from the results due to the change in ratio. (And if there are additional hosts one would expect to see RAs caused by sending RS as they connect; many router implementations multicast those solicited RAs.)
[SC>]   Yes, many implementation still multicast the solicited RA - I think that might be the case for this Ubuntu implementation too. Ankur-- do you remember?

I didn't quite understand the last part about changing the lifetime. 
That should not affect when RAs are transmitted (which the results show).
[SC>]  The advlifetime column is  kind of lame here.  Originally the plan was to observe the  node behavior  when RA interval is increased to  >= Advlifetime.  But  that was not possible from the configuration file [ did not allow]. So I believe Ankur tried changing default-lifetime just for experiment's sake . The change in number (increment) in RA is probably due to  increased time duration.

Also one observation was made (not listed in the draft) that  over several hours of duration only 2/% - 3% battery was consumed when the phone is left idle and periodic RA messages were sent. But the accuracy of the experiment was not clear. Perhaps it is because the phone sleeps and they don't listen to any of the multicast ND messages.
Ankur might have details on that.
Thanks,
-Samita

> Perhaps it could provide some data point for DAD issues as well.  I 
> have CC'ed Ankur if anyone has any questions/suggestions for him.
>
> -Samita
>
> >Name: draft-sood-6man-nd-signalling-n-dad-test
> > Revision:       00
> > Title:          Test result analysis of IPv6 Neighbor Discovery in a
> > simple Wireless network
> > Document date:  2015-03-09
> > Group:          Individual Submission
> > Pages:          14
> > URL:
> > 
> http://www.ietf.org/internet-drafts/draft-sood-6man-nd-signalling-n-da
> d-test-00.txt
> > Status:
> > 
> https://datatracker.ietf.org/doc/draft-sood-6man-nd-signalling-n-dad-t
> est/
> > Htmlized:
> > http://tools.ietf.org/html/draft-sood-6man-nd-signalling-n-dad-test-
> > 00
> >
> >
> > Abstract:
> >    IPv6 WG is looking into various Neighbor Discovery (ND) optimization
> >    techniques.  This document describes several test cases and test
> >    results on IPv6 ND number of messages, power usages using simple WiFi
> >    configuration and wireless phones as hosts.
>
>
>
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