Re: [v6ops] I-D Action: draft-gont-v6ops-ipv6-addressing-considerations-00.txt

Gert Doering <> Thu, 31 December 2020 10:30 UTC

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Date: Thu, 31 Dec 2020 11:30:10 +0100
From: Gert Doering <>
To: Brian E Carpenter <>
Cc: Fernando Gont <>, IPv6 Operations <>,
Message-ID: <20201231103010.GL13005@Space.Net>
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Subject: Re: [v6ops] I-D Action: draft-gont-v6ops-ipv6-addressing-considerations-00.txt
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On Thu, Dec 31, 2020 at 02:00:33PM +1300, Brian E Carpenter wrote:
> 4. The following table attempts to show some of the distinctions
> involved (simplified). View in a fixed-width font. You may not
> agree with it...
> Unicast       Prefix      IID        Routeable   Announced
> address       assigned    assigned
> types         by          by
> -----------------------------------------------------------
> Link-local    fixed       host       no          no
>               by RFC
> ULA           user/RA     host or    yes         IGP only
>               (random)    DHCPv6
> GUA           IANA/RIR/   host or    yes         IGP,
>               ISP/user/RA DHCPv6                 BGP4 by policy

Indeed, I am not agreeing - as there is nothing that prevents ULAs from 
being transported by BGP.

We use ULAs for "services that must never reachable from the Internet",
and our routing being what it is, everything is transported by BGP - only
loopbacks in OSPF.  The difference is "do we announce it to other ASes?"

So maybe this should be "generally expected to be visible by other
networks on the Internet" (ULA: no, GUA: yes).

But that's neither precise nor does "expected" mandate anything - I might
want to announce our ULA prefix to our sister company, using eBGP, and
I might decide to not announce our GUA IPv6 PI /48 that we use for our
backbone infra "because people are not supposed to send packets there"...

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

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