Re: A common problem with SLAAC in "renumbering" scenarios

[Fernando Gont <[e-mail]>]

On 6/2/19 07:15, Nick Hilliard wrote:
> Christian Huitema wrote on 05/02/2019 22:10:
[....]>
> The choices seem to be:
> 
> 1) ensuring that if a device is disconnected and then reconnects to the
> same network, the device will be given the same lease,

We can provide advice to make this happen where possible.. however, this
is not enforceable....



> 2) the intermediate device remembers the old lease, compares it with the
> new lease and if they're different, invalidates the old prefix by
> issuing an updated PIO,

Same here.



> 3) pushing the smarts down to the host layer and detecting / monitoring
> whether any particular prefix is still valid

This is the part that makes more sense to me -- although it doesn't mean
we don't do 1) and 2).




> Fernando's suggestion is workable but requires CPE vendors to get on
> board with the idea of storage of addressing information.  Getting ISPs
> to change DHCPv6 assignment policies is also workable, but requires
> centralised provisioning and dynamic routing.
> 
> None of these is ideal and all of them require compromise and some
> change in behaviour in a way that has side effects.
> 
> This is because the core problem is about how to deal with transfer of
> state information.  Managing state is always a monumental headache.

Exactly.


-- 
Fernando Gont
SI6 Networks
e-mail: [e-mail]
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