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

"Pascal Thubert (pthubert)" <> Fri, 08 June 2012 19:18 UTC

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From: "Pascal Thubert (pthubert)" <>
To: Michael Richardson <>, "" <>
Thread-Topic: [Roll] Ralph's DISCUSS on MRHOF spec
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Date: Fri, 08 Jun 2012 19:18:37 +0000
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Subject: Re: [Roll] Ralph's DISCUSS on MRHOF spec
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Hi Michael:

My understanding is that it is simpler to just check the OCP than first match the OCP in the config option and then go figure the metric in the metric option.
Not that it is a huge overhead but I fail to understand why you claim that the single OCP is simpler.
And no, I do not see that splitting in a future when implementations are already shipping will be easy; 
a mixed deployment would have to fall back to legacy from the root down, meaning that it will hardly ever evolve. 
LLN Devices that we install now some of the deployments (eg industrial) are expected last for 20+ years with minimum (no) intervention on them but maybe battery changes.



-----Original Message-----
From: [] On Behalf Of Michael Richardson
Sent: vendredi 8 juin 2012 16:12
Subject: Re: [Roll] Ralph's DISCUSS on MRHOF spec

>>>>> "Philip" == Philip Levis <> writes:
    Philip> I agree that this is a good question to ask. I disagree that
    Philip> now is an appropriate time to answer it definitively; we
    Philip> currently have only one OCP. We made a concrete and
    Philip> deliberate design decision. I'd argue we should stick with
    Philip> it to at least see it play out a bit more. E.g., once MRHOF
    Philip> is actually a proposed standard and we have significant
    Philip> experience using it. It's so critical in systems design to

I think what you are saying is that splitting MRHOF into multiple OCPs in the future would not be so difficult a thing to do.

There is a coding simplicity in what we have now, and we should be conscious of the constraints of our devices.

Michael Richardson <>, Sandelman Software Works 
IETF ROLL WG co-chair.