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

Fernando Gont <fgont@si6networks.com> Fri, 01 November 2019 13:41 UTC

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To: Mark Smith <markzzzsmith@gmail.com>, Philip Homburg <pch-v6ops-9@u-1.phicoh.com>
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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 1/11/19 08:12, Mark Smith wrote:
> 
> 
> On Fri, 1 Nov 2019, 21:42 Philip Homburg, <pch-v6ops-9@u-1.phicoh.com
> <mailto:pch-v6ops-9@u-1.phicoh.com>> wrote:
> 
>     > > "Hope" doesn't make networks run properly.
>     >
>     > This isn't "Hope", this is breaking promises, and that does break
>     > networks. If you can't at least trust that promises are intended
>     > to be kept then you have no network at all...
> 
>     Maybe somebody can do a text analysis and show which promise is broken.
> 
>     The typical case is a CPE rebooting, requesting a prefix using
>     DHCPv6 and
>     getting a different prefix from before.
> 
> 
> It shouldn't be. That's why clients have DHCP Unique Identifiers (DUIDs)
> that should be persistent across client restarts (or CPE reboots).

RFC7844 might lead to non-stable DUIDs. You might argue that that in
some scenarios you wouldn't do this (non-portable CPEs), but in others
(portable ones) you might.

-- 
Fernando Gont
SI6 Networks
e-mail: fgont@si6networks.com
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