Re: [Roll] DIS for given parent in draft-thubert-roll-eliding-dio-information

["Li Zhao (liz3)" <[e-mail]>]

Hello Rahul,

Node can store preferred parent's info when outage. 
But after reboot, it still need DIO from this parent to confirm whether this parent is alive. Because parent may be outage too.
Reset trickle timer can let parent inform all children and accelerate the network recovery. Otherwise, all nodes need to run unicast DIS request and unicast DIO response. It wastes too much of time. 

Does it make sense?

Best regards,
Li


On 2019/11/20, 11:52, "Roll on behalf of Rahul Jadhav" <[e-mail] on behalf of [e-mail]> wrote:

    Thanks Li for elaborating.
    
    Regarding the warm boot use-case you mentioned, the nodes certainly do
    not know whether they have individually rebooted or rebooted because
    of mass-outage.
    What I don't get is, if the child node already knows who the parent is
    why would it want to reset its Trickle timer?
    
    On Wed, 20 Nov 2019 at 11:31, Li Zhao (liz3) <[e-mail]> wrote:
    >
    > Hello Rahul,
    >
    > This is about " we need other nodes sending DIS to backoff on hearing other node's DIS ".
    > The use case is for warm boot case when hundreds of nodes power outage at the same time.
    > 1. Child nodes send DIS to inform given parent to reset its trickle. (unicast or multicast DIS both work)
    > 2. Child nodes suppress or backoff sibling nodes' DIS. Only multicast DIS works.
    >     And we need enhance Solicited Information option to identify this kind of DIS.
    >
    >
    > Best regards,
    > Li
    >
    > On 2019/11/19, 18:20, "Roll on behalf of Rahul Jadhav" <[e-mail] on behalf of [e-mail]> wrote:
    >
    >     Hi Li,
    >
    >     What is the use-case where the child node needs to inform the parent
    >     to reset its trickle unilaterally when it already knows the parent's
    >     address?
    >     Please find my comments below.
    >
    >     Best,
    >     Rahul
    >
    >     On Tue, 19 Nov 2019 at 13:34, Li Zhao (liz3) <[e-mail]> wrote:
    >     >
    >     > Hello all,
    >     >
    >     >
    >     >
    >     > As we discussed today, there is a requirement that node sends out multicast DIS to only reset given parent’s Trickle.
    >
    >     [RJ] We discussed today that we need other nodes sending DIS to
    >     backoff on hearing other node's DIS. We also discussed that we need
    >     parent node to not keep on resetting the trickle timer all the time on
    >     hearing DIS.
    >     I am not sure we discussed about sending a multicast DIS to reset a
    >     given parent's Trickle. Or may be I didn't get it correctly. Can you
    >     please elaborate? Thanks
    >
    >     >
    >     >
    >     >
    >     > Can we enhance Solicited Information option to add a flag to identify given parent’s address as following?
    >     >
    >     >
    >     >
    >     >         0                   1                   2                   3
    >     >
    >     >         0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    >     >
    >     >        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    >     >
    >     >        |   Type = 0x07 |Opt Length = 19| RPLInstanceID |V|I|D|P| Flags |
    >     >
    >     >        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    >     >
    >     >        |                                                               |
    >     >
    >     >        +                                                               +
    >     >
    >     >        |                                                               |
    >     >
    >     >        +                            DODAGID                            +
    >     >
    >     >        |                                                               |
    >     >
    >     >        +                                                               +
    >     >
    >     >        |                                                               |
    >     >
    >     >        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    >     >
    >     >        |Version Number | Parent Address     (16bytes)                  |
    >     >
    >     >        +-+-+-+-+-+-+-+-+                                               +
    >     >
    >     >        +                                                               +
    >     >
    >     >        |                                                               |
    >     >
    >     >        +                                                               +
    >     >
    >     >        |                -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    >     >
    >     >        +-+-+-+-+-+-+-+-+
    >     >
    >     >
    >     >
    >     > P flag: One Bit, indicates DIS request response from given parent
    >     >
    >     >
    >     >
    >     >
    >     >
    >     > Best regards,
    >     >
    >     > Li
    >     >
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