Re: [Roll] Ralph's DISCUSS on MRHOF spec

Philip Levis <pal@cs.stanford.edu> Fri, 08 June 2012 22:45 UTC

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From: Philip Levis <pal@cs.stanford.edu>
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Date: Fri, 8 Jun 2012 15:42:51 -0700
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To: Pascal Thubert (pthubert) <pthubert@cisco.com>
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Subject: Re: [Roll] Ralph's DISCUSS on MRHOF spec
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Response inline.

On Jun 8, 2012, at 1:03 PM, Pascal Thubert (pthubert) wrote:

> 
> With respect to 2), I'd love to hear from the folks implementing MRHOF whether they think this is a good idea. Are there cases where the flexibility is useful? ETX is stated as the least common denominator through a SHOULD. My worry right now is that we're pursuing a not-unreasonable-but-mostly-hypothetical concern. As I said before, asking the question is great, but we don't want to reverse years of agreed-upon-reasoning and tradeoff decisions without careful thought.
> 
> [Pascal] Agreed with the mostly hypothetical. Is anyone using another metric than ETX? But " years of agreed-upon-reasoning and tradeoff decisions" might be slightly exaggerated...
> 
> Cheers,
> 
> Pascal

What I meant here is that the rest of the protocol has been designed assuming this is the case. There are other things we might have done were there a strong binding between the two. For example, if an OCP defines the metric container and there isn't flexibility, there would be little need for a general metric container object: an OF could define it. 

I'll repeat what I said before: we should ask this question, but should not answer it definitively now. Making a significant change right now based on concerns -- which haven't been voiced by any implementers -- seems like a dangerous road to tread. I mean, come on, let's evaluate the design and evolve it from practice, not from the sofa.

Phil