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

Philip Homburg <pch-v6ops-9@u-1.phicoh.com> Fri, 01 November 2019 10:41 UTC

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Date: Fri, 01 Nov 2019 11:41:52 +0100
Archived-At: <https://mailarchive.ietf.org/arch/msg/v6ops/kAzjYYSCJhhOF_Llh1TasVRbgwE>
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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> > "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.

As far as I know, there is no text that requires a DHCPv6 server to return
the previous lease if it is still valid.

The next question would be, if the CPE would try to renew the old prefix and
the DHCPv6 server declines. Is there any text the requires a DHCPv6 server
to do that.

Then the question is, if a CPE reboots can it continue to use the old lease?
Typically, link attachment requires obtaining a new lease. But I don't know
if that is specified anywhere. 

I do know that some routers do not install a forwarding entry if you don't 
get a new lease. I don't think we have any spec for that.

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