Re: [6lo] Barry Leiba's Discuss on draft-ietf-6lo-deadline-time-04: (with DISCUSS and COMMENT)

Charlie Perkins <> Fri, 31 May 2019 02:37 UTC

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To: Carsten Bormann <>
Cc: Barry Leiba <>, The IESG <>,,, Samita Chakrabarti <>, Shwetha Bhandari <>,
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From: Charlie Perkins <>
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Date: Thu, 30 May 2019 19:37:28 -0700
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Subject: Re: [6lo] Barry Leiba's Discuss on draft-ietf-6lo-deadline-time-04: (with DISCUSS and COMMENT)
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Hello Carsten,

Thanks for pointing out that typo.  The expressions should have been 
"4..64-bit" in both cases.  It's amazing how often we can look at the 
text and still miss obvious mistakes.

Charlie P.

On 5/12/2019 11:49 AM, Carsten Bormann wrote:
> On May 12, 2019, at 15:54, Barry Leiba via Datatracker <> wrote:
>> Why is DTL the length *minus 1*?  Doesn’t that invite mistakes?  Is there a
>> reason not to make it the length, and to say that 0 is not a valid value?
> Fundamentally, a small integer encoded into a bitfield is best encoded as a value starting from 0, instead of creating holes at the bottom *and* the top.  Also, in this case, the 4-bit value encoding DTL can be between 0 and 15, so the length in bits could be 0 to 60, which is not enough for 64 bits.
> So adding one sounds fine, even if you believe holes are good.
> But then, I don’t understand why both DT and OTD are said to be “8..64” bits — that needs 15 possible values, not 16; OTL has only 3 bits (which cannot express 15 possible values, which are probably not needed anyway), and the example for OTL has a DT of 4 bits.
> Grüße, Carsten