Re: [Roll] enrollment priority

Michael Richardson <mcr+ietf@sandelman.ca> Thu, 25 November 2021 20:54 UTC

From: Michael Richardson <mcr+ietf@sandelman.ca>
To: Routing Over Low power and Lossy networks <roll@ietf.org>
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Date: Thu, 25 Nov 2021 15:53:50 -0500
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Archived-At: <https://mailarchive.ietf.org/arch/msg/roll/jFdftrdSoKNU7hlVrltBkHbkUQY>
Subject: Re: [Roll] enrollment priority
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Pascal Thubert \(pthubert\) <pthubert=40cisco.com@dmarc.ietf.org> wrote:
    > (https://mailarchive.ietf.org/arch/msg/roll/2MaZ4wXLVzJbmLC-LO6c--DsbWQ/)
    > Konrad Iwanicki <iwanicki@mimuw.edu.pl> wrote:
    konrad> - How do changes to min priority (and OSN) affect DIO Trickle timers?
    konrad> [OSN == the lollipop sequence counter]

    konrad> I think that if we have the counter, that increments the OSN reset the trickle
    konrad> timer, but Pascal suggests an additional bit to reset the
    konrad> trickle?

    pt> Some casual updates do not deserve to be flooded faster than normal
    pt> stable DIO. But emergency and network control ones should. So we need a
    pt> trigger to say that this DIO message should reset trickle. May that bit
    pt> should not be in that option. It could be more generically used in
    pt> DIOs.

    mcr> We can certainly build these rules into enrollment priority option.
    mcr> But, I wonder if resetting trickle has general application, and should actually be
    mcr> signaled by inclusion of a new DIO option.

    pt> Oups i read this after thinking the same. I agree.

okay, I'll include this.

    konrad> - How does a (temporal) lack of a preferred parent affect the proxy
    konrad> priority of the node in EBs (and in general, the node's behavior)?

    mcr> If the node can't send traffic up to the root, then I think that it should
    mcr> turn off EBs until it can.

    pt> Yes; at least advertise 7F for the priority if it needs to beacon for other reasons

I agree, 7F (infinite) if it needs to beacon.
Should it even beacon if it has no feasible parents?

    mcr> In a 6tisch situation, it is likely that the lack of a preferred parent is
    mcr> probably due to falling out of the schedule.

    pt> Yes

    Pascal> A node that does not have a feasible parent should poison or
    Pascal> detach. It does not make sense for a detached node to take
    Pascal> visitors. So probably it should beacon a join priority of 0x7F.

    mcr> Does detach mean to send a DIO with infinite rank?

    pt> Poison means that. Detaching means forming its own dodag with the G
    pt> bit not set (not grounded)

    mcr> I'm undecided if it should send a beacon at all.
    mcr> https://github.com/roll-wg/draft-ietf-roll-enrollment-priority/issues/11

There seem to be a number of parts to a decision tree here.

I will start more threads.

--
Michael Richardson <mcr+IETF@sandelman.ca>   . o O ( IPv6 IøT consulting )
           Sandelman Software Works Inc, Ottawa and Worldwide

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[Roll] enrollment priority Michael Richardson
Re: [Roll] enrollment priority Konrad Iwanicki
Re: [Roll] enrollment priority Rahul Jadhav
Re: [Roll] enrollment priority Pascal Thubert (pthubert)
Re: [Roll] enrollment priority Konrad Iwanicki
Re: [Roll] enrollment priority Pascal Thubert (pthubert)
Re: [Roll] enrollment priority Konrad Iwanicki
Re: [Roll] enrollment priority Pascal Thubert (pthubert)
[Roll] alternates to enrollment priority Michael Richardson
Re: [Roll] enrollment priority Michael Richardson
Re: [Roll] alternates to enrollment priority Pascal Thubert (pthubert)
Re: [Roll] enrollment priority Pascal Thubert (pthubert)
Re: [Roll] enrollment priority Konrad Iwanicki
Re: [Roll] enrollment priority Michael Richardson
Re: [Roll] enrollment priority Konrad Iwanicki
Re: [Roll] enrollment priority Michael Richardson

Re: [Roll] enrollment priority

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