Re: [v6ops] Stability and Resilience (was Re: A common...)

[Lee Howard <[e-mail]>]

On 2/22/19 12:04 PM, Owen DeLong wrote:
>>
>> Networks should, as much as possible, be resilient to prefix changes. 
>> Some things networks can do to improve resilience:
>>
>> 1.
>>
>>     Write a learned prefix to non-volatile memory and issue a DHCPv6
>>     Renew for that prefix on reboot.
>>
>> 2.
>>
>>     Use dynamic DNS and shorter TTLs.
>>
>> 3.
>>
>>     Implement something like NETCONF to distribute prefix information
>>     to policy devices like firewalls or SD-WAN controllers. I think a
>>     separate document describing this application of NETCONF would
>>     make sense.
>>
>
> If the prefix is written to nv men, wouldn’t it also be possible for 
> implementers to send rapid deprecation RAs for any prefix not renewed?
>
> In other words, after reboot, try to reacquire same prefix. If that 
> doesn’t work, when you advertise the new prefix, you could also 
> include the old prefix with a very short preferred and valid lifetime 
> (e.g. 1 second) in the first RA, which should be sent to the all nodes 
> on link multicast?
>
> It doesn’t eliminate the problem, but 1 second additional duration 
> would be barley noticeable amid the minute or so it takes most home 
> gateways to reboot.

I like this suggestion; don't think I'd seen it before.

"Write a learned prefix to non-volatile memory and issue a DHCPv6 Renew 
for that prefix on reboot. If renew fails, send new RAs for that prefix 
with a preferred lifetime of 0, and a valid lifetime of two hours."

Lee

>
> Owen
>