Re: [Roll] Way forward for draft-clausen-lln-rpl-experiences

Philip Levis <pal@cs.stanford.edu> Wed, 16 May 2012 17:02 UTC

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From: Philip Levis <pal@cs.stanford.edu>
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Date: Wed, 16 May 2012 10:02:56 -0700
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References: <258D7E2F-F0C7-49EA-B831-81070C86EDB3@thomasclausen.org> <2257A578-B2DF-4145-8393-9BB5D7E1CFBD@cisco.com> <2225986E-992E-43C7-B0CA-9CDA91CE1F3A@thomasclausen.org> <B1B81482-0F7E-4BCE-BBA7-B21949E3C16C@cisco.com> <0958556A-7D9A-4E8B-8091-1D6EC0B813B4@thomasclausen.org> <ACBA7834-F4A1-4D9C-80D6-E76C793A6770@cisco.com>
To: JP Vasseur <jpv@cisco.com>
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Cc: roll WG <roll@ietf.org>, Michael Richardson <mcr@sandelman.ca>
Subject: Re: [Roll] Way forward for draft-clausen-lln-rpl-experiences
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On May 16, 2012, at 6:54 AM, JP Vasseur wrote:
> 
> Well put it differently, it would be beneficial to provide more details on your testing scenarios for the WG to make sure that nothing 
> is "scenario-dependent" and to make sure that the outcome could indeed apply to all scenarios, it might be worth being more explicit.
> 
> Could you do that before polling the WG ?

I think an example of what JP's talking about might be something such as the question I raised in Paris: what constitutes a "down link" in the testing? Thomas' response was "no ack after L2 retransmissions"; this is an assumption about behavior. How many retransmissions? What was the time spacing? It's not hard to configure 802.11, for example, such that L2 back off has only a tiny chance of successful delivery in the case of a hidden terminal. Most wireless protocol implementations today understand these issues and rely on much longer time frames to consider a link "down."

Phil