Re: [v6ops] SLAAC renum: Problem Statement & Operational workarounds

Fernando Gont <> Fri, 25 October 2019 18:05 UTC

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To: Ole Troan <>, Philip Homburg <>
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From: Fernando Gont <>
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Date: Fri, 25 Oct 2019 15:04:23 -0300
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Subject: Re: [v6ops] SLAAC renum: Problem Statement & Operational workarounds
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On 25/10/19 10:25, Ole Troan wrote:
>>> The changes in the transport and application layers are already 
>>> happening (e.g. QUIC).
>> If QUIC can deal with this flash renumbering problem then it would be nice
>> to see a report on that. I'm very curious how to would work.
>> In any case, there will continue to be a lot of TCP and non-QUIC UDP in
>> the coming years. Are you saying that it will be cheaper to modify all
>> transport protocols than to fix it in the IPv6 stack?
> It can't be fixed in the IPv6 stack.

When what you call "flash-renumbering" happens, hosts continue employing
addresses and network configuration that is stale incorrect. That's the
problem. As soon as you are able to detect that and unprefer/remove such
addresses/configuration, you've solved the problem.

That's what we're trying to do here.

> My argument is that if you do that, as in add support for ephemeral addressing / flash renumbering at the network layer, without doing anything at upper layers, then for an end-user, IPv6 will provide no value or more likely negative value compared to IPv4 + NAT.

The two are orthogonal. Upper-layers can/should do better. That doesn't
mean that we shouldn't improve robustness at the network layer.

Fernando Gont
SI6 Networks
PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492