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

IJsbrand Wijnands <> Tue, 04 November 2014 22:28 UTC

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From: IJsbrand Wijnands <>
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Date: Tue, 04 Nov 2014 14:28:12 -0800
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To: Carsten Bormann <>
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Subject: Re: [Roll] [Bier] Source-Routed Multicast
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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.



On 03 Nov 2014, at 15:42, Carsten Bormann <> 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
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