Re: [Roll] [Bier] Source-Routed Multicast

State  in BIER (one bitmap per child) is so limited and controlled that a constrained node that cannot do storing may be able to still do BIER. For such devices, we could propose a new mode of operation for RPL that is BIER only, for both unicast and multicast traffic.

If the preferred parent tree is acceptable for downward traffic, the DAOs would percolate up by ORing the bitmaps of the children and passing that to the preferred parent. Decision to forward down to a child (or of a child to process an incoming message) would be a simple AND of the bitmap in the packet and that of the child, regardless of unicast or multicast.

Cheers,

Pascal

> -----Original Message-----
> From: Roll [mailto:roll-bounces@ietf.org] On Behalf Of IJsbrand Wijnands
> (iwijnand)
> Sent: mardi 4 novembre 2014 14:28
> To: Carsten Bormann
> Cc: Andrzej.Duda@imag.fr; roll@ietf.org; bier@ietf.org; 6lo@ietf.org
> Subject: Re: [Roll] [Bier] Source-Routed Multicast
> 
> Hi Carsten,
> 
> The ROLL case looks very interesting.
> 
> Just one clarification, BIER is not Source-Routed multicast. i.e. we don't include
> a list of hops that the packet needs to follow, we only include final destination in
> the form of Bit Positions, and each router along the path does a lookup on the
> Bit Position to determine where the packet is to be sent.
> 
> Thx,
> 
> Ice.
> 
> On 03 Nov 2014, at 15:42, Carsten Bormann <cabo@tzi.org> wrote:
> 
> > In Hawaii, there will be a BOF about a multicast forwarding control
> > scheme where a router on the way prefixes a multicast packet with a
> > special header that tells downtree routers where to forward the
> > multicast - Bit Index Explicit Replication, or BIER.
> >
> > While BIER appears to be very focused on a carrier or datacenter
> > perspective (see draft-kumar-bier-use-cases and the other
> > draft-*-bier-*), there are applications in constrained node networks
> > that would benefit from source-routed multicast.
> >
> > Several proposals on how to do source-routed multicast in constrained
> > node networks are getting ready for consumption.
> >
> > With its current focus, I don't think the BIER BOF itself is the right
> > place to have a technical discussion about this.
> > There is no ROLL meeting in Hawaii.
> > The 6lo agenda is almost full.
> > Should we do this in a side meeting?  (If we do this before Tuesday,
> > we can at least report in 6lo - if we do it on Sunday, we might even
> > have an opinion to air during the BIER BOF.)
> >
> > Grüße, Carsten
> >
> > _______________________________________________
> > BIER mailing list
> > BIER@ietf.org
> > https://www.ietf.org/mailman/listinfo/bier
> 
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