Re: [v6ops] Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-ipv6-ula-scope-00.txt)

Ted Lemon <> Sat, 20 February 2021 14:42 UTC

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From: Ted Lemon <>
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Subject: Re: [v6ops] Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-ipv6-ula-scope-00.txt)
Date: Sat, 20 Feb 2021 09:42:54 -0500
In-Reply-To: <YDEX/Uu9X2hm+RX/@Space.Net>
Cc: Fernando Gont <>, IPv6 Operations <>, "" <>
To: Gert Doering <>
References: <> <> <> <> <> <> <> <YDEX/Uu9X2hm+RX/@Space.Net>
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On Feb 20, 2021, at 9:09 AM, Gert Doering <> wrote:
> In practice, how much IPv6 multicast is there which is not "node" and
> "link" scoped?  Or, to be even more picky, not "link" scoped?

It’s being used in the context of IoT to do mass events, like turning on all the lights in a context where the switch is on link A, and some lights are on links B and C, for example. The motivation for doing this is that in principle multicast uses less of the constrained bandwidth of the IoT network. This can work because even when this sort of partition happens, there is a common infrastructure backbone that can handle the multicast routing issues. The old dream of multicast video on the internet seems to be dead, but that doesn’t mean that off-link multicast is never useful.