Re: [v6ops] A broken promise - "You said PD Prefix Valid Lifetime is going to be X" (Re: SLAAC renum: Problem Statement & Operational workarounds)

Ted Lemon <> Fri, 01 November 2019 12:20 UTC

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From: Ted Lemon <>
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Date: Fri, 1 Nov 2019 08:20:53 -0400
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To: Ole Troan <>
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Subject: Re: [v6ops] A broken promise - "You said PD Prefix Valid Lifetime is going to be X" (Re: SLAAC renum: Problem Statement & Operational workarounds)
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On Nov 1, 2019, at 7:15 AM, Ole Troan <> wrote:
> This is how IPv6 renumbering has been specified for 20 years... I presume that was not news?

There have been efforts in the IETF to document how renumbering can be done in as minimally disruptive a way as possible (see e.g. Steinar’s message).   There are ISPs that believe that they are supposed to renumber end user addressing regularly to prevent (or at least complicate) prefix-based user tracking.  And there are ISPs that, if Fernando is to believed, and I think he is, do flash renumbering.

RFC 4192 doesn’t specify timeframes.   I think it’s a good document, but it doesn’t actually prescribe any detailed behavior.

So if none of the options I suggested have IETF consensus, is the answer to say “then we just assume that people will do whatever they want, and if they break things we’re okay with that?”