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

[Owen DeLong <[e-mail]>]

> On Oct 31, 2019, at 12:25 PM, Fernando Gont <[e-mail]> wrote:
> 
> On 27/10/19 10:54, Ted Lemon wrote:
>> On Oct 27, 2019, at 9:41 AM, Philip Homburg <[e-mail]
>> <mailto:[e-mail]>> wrote:
>>> The little bit missing is that the CPE should write prefixes
>>> advertised using
>>> SLAAC to persistent storage which allows the CPE to invalidate stale
>>> prefixes
>>> after a reboot.
>> 
>> Actually I do not believe this is correct behavior.   Let us assume
>> prefix delegation.   If we have prefix delegation, then when the CPE
>> comes back from a power cycle, it should reconfirm the prefix it had
>> previously; the assumption is that that prefix is still valid.  This can
>> be handled in infrastructure—the ISP edge router should know whether the
>> prefix is still valid, because if it is it should be advertising a route
>> for it.   If it is not still valid, then the CPE router should attempt
>> to renew it, which would go to the DHCP server (possibly both messages
>> would).
> 
> That assues the CPE has stored the previously-leased prefix on stable
> storage -- which does not need to be the case. Hence the related text in
> our I-D.

IMHO, the CPE requirements should be increased and the CPE should be required
to store the prefix and it’s expected valid and preferred expiration times in persistent
storage. I would like to see the text in the I-D updated accordingly.

Owen
>