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

Gert Doering <> Thu, 25 February 2021 16:59 UTC

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Date: Thu, 25 Feb 2021 17:59:15 +0100
From: Gert Doering <>
To: Owen DeLong <>
Cc: Gert Doering <>, Fernando Gont <>, "Manfredi (US), Albert E" <>, IPv6 Operations <>, "" <>
Subject: Re: [v6ops] Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-ipv6-ula-scope-00.txt)
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On Tue, Feb 23, 2021 at 03:18:44PM -0800, Owen DeLong 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?
> A lot less than there should be.

I beg to differ on that...  among all the problems IPv6 has, "lack of
multicast" is not one...

Wide-scale routed multicast is a very nice idea, but totally non-deployable
across network boundaries in reality.  We've tried, for many years (with
IPv4), and every time a customer wanted to use it, it was broken in some
non-debuggable way (like, RP-Tree selecting a path in 3549 where they forgot
to turn on PIM on the interfaces...).

Even on-link multicast gets broken by switch vendors often enough.

Gert Doering
        -- NetMaster
have you enabled IPv6 on something today...?

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