Re: graceful renumbering of CPE networks

[Mikael Abrahamsson <[e-mail]>]

On Mon, 25 Feb 2019, Ole Troan wrote:

>
>
>> On 25 Feb 2019, at 00:26, Michael Richardson <[e-mail]> wrote:
>>
>> The part that is missing is some kind of "push" notification from the ISP to
>> the CPE that new addresses are available.  That need not obsolete the
>> old addresses --- the lifetime contract can be maintained.
>
> DHCP Reconfigure.

In the most common deployment scenario there is:

HGW <-> ISP-ROUTER <-> something <-> DHCPv6-server

Normal message flow is

HGW->ISP-ROUTER->DHCPv6-server which then answers back with 
DHCPv6-SERVER->ISP-router->HGW

In both ways the ISP-ROUTER is a DHCPv6 relay which does snooping on the 
relayed packets and installs routes as per the IA_NA/PD information flying 
by.

What mechanism in this deployment scenario would initiate a DHCP 
Reconfigure when the ISP-ROUTER is re-booted? I know there is some kind of 
"ok, I've lost state, please fill me in" kind of question that the relay 
can ask the server, but should we then tack on that when this happens (and 
it should then happen by default at start-up) a dhcp reconfigure message 
should be sent to the client?

What if both DHCP server and relay has lost state, can it even tell the 
HGW to refresh?

-- 
Mikael Abrahamsson    email: [e-mail]