Re: [6lo] WG Last Call on draft-ietf-6lo-multicast-registration-11

["Pascal Thubert (pthubert)" <[e-mail]>]

Oh!

Well, at least there's text for that. The next paragraph is about incrementing the TID when resending, but not the way a real TID operates, quoting
"
      In an unreliable environment, the multicast NA(EARO) message may
      be resent in a fast sequence, in which case the TID must be
      incremented each time.  A 6LN that has recently processed the
      NA(ARO) ignores the NA(EARO) with a newer TID received within the
      duration of the fast sequence.  That duration depends on the
      environent and has to be configured.  By default, it is of 10
      seconds.
"

Now that I think about it I should make it compliant with real TID operations (https://www.rfc-editor.org/rfc/rfc6550#section-7.2) so the 6LN/LFN would figure it is no more in sync with the 6LR/FFN just because the two sequence numbers are determined not to be comparable.

If that fits your need I can update the text in that direction, say that the 6LR sets the TID field in the broadcast NA(EARO) like it would for NS(EARO), following section RPL 7.2, that there should be several in a short time after reboot, and that the 6LN keeps track of the 6LR TID, and considers that he needs to reregister if the TID in a new NA is not comparable.

Would that help?

Pascal  


> -----Original Message-----
> From: 6lo <[e-mail]> On Behalf Of Falendysz, Gene
> Sent: vendredi 18 novembre 2022 15:16
> To: Pascal Thubert (pthubert) <pthubert=[e-mail]>;
> [e-mail]
> Subject: Re: [6lo] WG Last Call on draft-ietf-6lo-multicast-registration-11
> 
> Hi Pascal,
>   The problem I am trying to solve is that currently Wi-SUN FAN is
> specifying that once a node responds to a NA(EARO) (request to reregister)
> it ignores all others for 5 minutes. This is to minimize flooding. The
> problem with that approach is that it is not uncommon for a meter to
> experience several power cycles when reclosers are trying to isolate a
> fault in the grid. The 5 minute ignore period would mean that it is
> possible for a node to ignore a valid request. I am hoping that the TID can
> be used to indicate when the request is new and not a repeat of the
> previous request, incrementing with each power cycle.
> 
> Best regards,
> 
> Gene Falendysz
> Office:[phone] / Mobile: [phone]
> 
> -----Original Message-----
> From: Pascal Thubert (pthubert) <pthubert=[e-mail]>
> Sent: Friday, November 18, 2022 6:09 AM
> To: Falendysz, Gene <[e-mail]>; [e-mail]
> Subject: [EXTERNAL] RE: [6lo] WG Last Call on draft-ietf-6lo-multicast-
> registration-11
> 
> Hello Gene:
> 
> The intention in the TID is to sequence the mobility of the target address
> exposed in NS(EARO). NA (EARO) is supposed to respond unicast to the
> NS(EARO), or be used as an asynchronous response to that NS. IOW, this
> broadcast NA about target=self is new, and the fields have no specified
> meaning / behavior.
> 
> Certainly the expectation is that the TID field would still contain a TID
> associated with the target address, and I'll be happy to write that if you
> have a case. I did not see one so I just applied the "reserved" behaviour.
> 
> Is it your intention that the TID is the same as in NA(EARO) and reflects a
> counter that the router maintains for its LLA?
> 
> All the best;
> 
> Pascal
> 
> 
> > -----Original Message-----
> > From: 6lo <[e-mail]> On Behalf Of Falendysz, Gene
> > Sent: jeudi 17 novembre 2022 15:44
> > To: Pascal Thubert (pthubert) <[e-mail]>; [e-mail]
> > Subject: Re: [6lo] WG Last Call on
> > draft-ietf-6lo-multicast-registration-11
> >
> > Hi Pascal,
> >   In section 7.3 is this statement:
> > "That asynchronous NA(ARO) SHOULD be sent to the all-nodes link scope
> > multicast address (FF02::1) and Target MUST be set to the link local
> > address that was exposed previously by this node to accept
> > registrations, and the TID MUST be set to 0."
> > Why the "and the TID MUST be set to 0"? We need the TID to do
> > duplicate detection on the asynchronous NA(ARO).
> > In the metering world it is not uncommon for a node to power cycle
> > several times as reclosers try to isolate faults.
> >
> > Cheers,
> >
> > Gene Falendysz
> > Office:[phone] / Mobile: [phone]
> >
> >
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> 
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