Re: [core] Chair's review of draft-ietf-core-hop-limit-02.txt

Carsten Bormann <> Sat, 23 February 2019 05:58 UTC

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From: Carsten Bormann <>
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Date: Sat, 23 Feb 2019 06:58:03 +0100
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To: Jim Schaad <>
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Subject: Re: [core] Chair's review of draft-ietf-core-hop-limit-02.txt
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On Feb 22, 2019, at 22:47, Jim Schaad <> wrote:
> My gut feeling is that the answer should be yes it should become a recommended option for all CoAP proxies.  I am not sure that this is the time for that to happen.  I think that in the next couple of years there may be a larger need to develop some BCPs for proxies and that would be the time to make the recommendation.

Right.  So the specific question for the WG is:

Are we ready to strongly recommend (on a “SHOULD deploy” level) hop-limit as our proxy loop mitigation technique now?

Or should we wait with such a recommendation until we have had a broader view at proxy requirements?  (E.g., then, MAYBE we might want to go for Via-like loop prevention instead — very big MAYBE, as Via is expensive with IPv6.)

I don’t have a strong opinion either way and therefore would like some more feedback from the WG.

In any case, the place in DOTS where it says how CoAP is used for DOTS should also say “please do deploy hop-limit where proxies are used” in the strength that the DOTS people are comfortable with.

While the hop-limit draft is not heavily associated with DOTS, maybe it would be useful to add some “not just for DOTS” language as well (after all, that was the point of splitting it out).

Grüße, Carsten