Re: [Roll-bier-dt] roll-bier-dt

[Tony Przygienda <[e-mail]>]

I thought it was all delayed until f2f in thailand ?

On Wed, Oct 24, 2018 at 8:46 AM Greg Shepherd <[e-mail]> wrote:

> I won't be on the call today, sorry.
>
> Greg
>
> On Fri, Oct 19, 2018 at 7:54 AM Pascal Thubert (pthubert) <
> [e-mail]> wrote:
>
>> Please consider this then :)
>>
>> https://datatracker.ietf.org/doc/draft-thubert-6lo-bier-dispatch/
>>
>> take care,
>>
>> Pascal
>>
>> > -----Original Message-----
>> > From: Toerless Eckert <[e-mail]>
>> > Sent: vendredi 19 octobre 2018 15:52
>> > To: Pascal Thubert (pthubert) <[e-mail]>
>> > Cc: Carsten Bormann <[e-mail]>; [e-mail]
>> > Subject: Re: [Roll-bier-dt] roll-bier-dt
>> >
>> > On Fri, Oct 19, 2018 at 01:20:11PM +0000, Pascal Thubert (pthubert)
>> wrote:
>> > > Sure, but the mystery to me is what goes transported with BIER.
>> >
>> > As said, BIER proper can encapsulate anything deemed important enough
>> to get
>> > a code point in the BIER encap. I am saying "proper" because ROLL may
>> not
>> > want to take RFC8296 given the likely competition with 6LowPan.
>> >
>> > > Because that is the heart of the problem we are facing in this DT..
>> > > If BIER transports a same IP packet to multiple destinations, then
>> they must all
>> > accept the same packet.
>> >
>> > More a property of the larger clas of multicasting overall assuming
>> tojust copy
>> > the payload - and not to modify it.
>> >
>> > I thought we had killed in last weeks meeting the idea of trying to
>> come up with
>> > a mechanism that manages to use packet replication (BIER) and then
>> modding
>> > received copies to fake different per-receiver IP unicast packets
>> > - because of the problem of making this architecturally work well with
>> higher
>> > layers like UDP that also have a notion of an IP (pseudo) header.
>> > Too much faking needed. At least thats what i tried to summarize in my
>> slides.
>> >
>> > Aka: We use BIER-TE for unicast packets but then the expectation is
>> that there is
>> > just one destination, and the whole purpose of BIER-TE is not
>> replication but
>> > source routing. And we use BIER-TE(/BIER) for IP multicast packets
>> where there
>> > can be 1 or more destinations.
>> >
>> > [ Of course there are fun extensions later, e.g.: a unicast packet
>> could  still be
>> > sent to redundant nodes sharing an IP adddress and therefore  able to
>> > receive/process the same packet, but i think thats less likely
>> something one
>> > would do in a ROLL domain. ]
>> >
>> > > Moreover, if the destination is not the router indicated by the bit
>> > > but a neighbor or a set of neighbors to that router, then the inner
>> > > packet must indicate that.
>> > > All in all, that tells me that the transported packet is IP multicast.
>> >
>> > Yes, we have two layers. The BIER layer that only reaches nodes with an
>> > assigned BIER bit, and they can communicate potentially any payload
>> across
>> > BIER, IP or other. And then on top of that there is IP multicast
>> between the BIER
>> > edge nodes and IP unicast/multicast only nodes. The pictures in the
>> slide deck
>> > posted intend to show that (that IP multicast building block picture
>> still TBD).
>> >
>> > > What do I miss?
>> >
>> > I think primarily me wanting to figure out the encap we use within the
>> BIER-
>> > ROLL domain: RFC8296 vs. 6LowPan+extensions.
>> >
>> > Cheers
>> >     Toerless
>> >
>> > > Take care,
>> > >
>> > > Pascal
>> > >
>> > > > -----Original Message-----
>> > > > From: Toerless Eckert <[e-mail]>
>> > > > Sent: vendredi 19 octobre 2018 15:14
>> > > > To: Pascal Thubert (pthubert) <[e-mail]>
>> > > > Cc: Carsten Bormann <[e-mail]>; [e-mail]
>> > > > Subject: Re: [Roll-bier-dt] roll-bier-dt
>> > > >
>> > > > On Fri, Oct 19, 2018 at 12:36:06PM +0000, Pascal Thubert (pthubert)
>> > wrote:
>> > > > > Hello Toerless:
>> > > > >
>> > > > > Well, there is as Carsten says a multicast support for RPL storing
>> > > > > mode, but not
>> > > > for non-storing. This is where Carsten's draft comes in to play.
>> > > >
>> > > > Sure. As said, i may not have correctly captured what Mcr was
>> > > > explaining,
>> > > >
>> > > > > In normal BIER, the bits indicate the routers, don't they? So
>> > > > > there's an IP
>> > > > packet inside, correct, like in my tunnel mode? But then I expect it
>> > > > is the same packet for all destinations. So how does htat work, is
>> > > > it a mcast packet or do all the destination have a same IP address?
>> > > >
>> > > > "Proper BIER" (TM) (the stuff done by BIER-WG) has defined its own
>> > > > encapsulation header (RFC8296) that sits on top of MPLS or ethernet
>> > > > and that has its own next-proto field/registry, so it can be
>> > > > followed by IP or anything else that BIER-WG feels deserves a code
>> point in
>> > that registry.
>> > > >
>> > > > Cheers
>> > > >     Toerless
>> > > >
>> > > > > Pascal
>> > > > >
>> > > > > > -----Original Message-----
>> > > > > > From: Roll-bier-dt <[e-mail]> On Behalf Of
>> > > > > > Toerless Eckert
>> > > > > > Sent: vendredi 19 octobre 2018 14:21
>> > > > > > To: Carsten Bormann <[e-mail] <cabo@tzi..org>>
>> > > > > > Cc: [e-mail]
>> > > > > > Subject: Re: [Roll-bier-dt] roll-bier-dt
>> > > > > >
>> > > > > > That was me taking notes what Michael said, and maybe i didn't
>> > > > > > transcribe it correctly. Hope Michael is subscribed here to
>> answer.
>> > > > > >
>> > > > > > I think i was more wondering about the suport of compressed IP
>> > > > > > multicast headders in 6LowPan because that is unclear to me and
>> > > > > > we probably need to take one of the DT meetings to detail more
>> > > > > > what extensions we need to do for 6LowPan to support BIER.
>> > > > > >
>> > > > > > Cheers
>> > > > > >     Toerless
>> > > > > >
>> > > > > > On Fri, Oct 19, 2018 at 07:45:50AM +0200, Carsten Bormann wrote:
>> > > > > > > On Oct 19, 2018, at 04:56, Toerless Eckert <[e-mail]>
>> wrote:
>> > > > > > > >
>> > > > > > > >
>> https://raw.githubusercontent.com/toerless/roll-bier/master/
>> <https://raw.githubusercontent..com/toerless/roll-bier/master/>
>> > > > > > > > note
>> > > > > > > > s/18
>> > > > > > > > 1017-roll-bier-notes.txt
>> > > > > > >
>> > > > > > > What do you mean with ???RPL does not support multicast.????
>> > MOP=3?
>> > > > > > > (That is of course storing mode only, and storing mode
>> > > > > > > doesn???t exist :-), so
>> > > > > > you have a point.
>> > > > > > > That???s why we did ccast, to fill in multicast for
>> > > > > > > non-storing
>> > > > > > > mode.)
>> > > > > > >
>> > > > > > > Grüße, Carsten
>> > > > > >
>> > > > > > --
>> > > > > > ---
>> > > > > > [e-mail]
>> > > > > >
>> > > > > > _______________________________________________
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>> > > >
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>> > >
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