Re: [dhcwg] DHCPv6 Failover -- LAST CHANCE

[tianxiang li <[e-mail]>]

Thank you for explaining this point. It does seem like the desirable
method, and a /64 is sufficient enough for address allocation, so  I
guess there's no need to address rebalancing.

Thanks,
Tianxiang

2016-09-08 21:09 GMT+08:00 perl-list <[e-mail]>:

>
>
> ------------------------------
>
> *From: *"tianxiang li" <[e-mail]>
> *To: *"Kim Kinnear" <[e-mail]>
> *Cc: *"dhcwg" <[e-mail]>
> *Sent: *Wednesday, September 7, 2016 10:37:06 PM
> *Subject: *Re: [dhcwg] DHCPv6 Failover -- LAST CHANCE
>
> 4.2.1 Independent allocation
>
>
>
> “In this allocation scheme, used for allocating individual IPv6 addresses,
> available IPv6 addresses are permanently (until server configuration
> changes) split between servers…”
>
>
>
> If active-passive mode is used, it would mean that the addresses in the
> secondary server would not be used unless the primary server fails. In that
> case, wouldn’t permanently splitting the addresses between the primary and
> secondary server a waste of addresses?
>
>
>
> If the address pool in the primary server becomes scarce, wouldn’t a
> rebalancing mechanism be useful?
>
>
> I read this section as just a codifying of what we do now without
> failover.  We put half the /64 on the "primary" and half on the
> "secondary".  It provides for some enhanced behavior where clients won't
> need to get a new address in the case of server failure as the remaining
> server can renew addresses.  Also, you wouldn't need to do any math as the
> server would arithmetically split in half for you any subnets that are
> marked for this behavior.  If offered a choice in the future, I would
> probably choose this method as it is the simplest.
>
> Also, this bit here: "It also assumes that the pool assigned to each
> server will never deplete." negates your comment about addresses becoming
> scarce.  It is highly recommended (by all articles and documentation that
> I've seen) that all end networks be configured as /64 subnets.  There are
> quite a lot of addresses in a /64.  More than are in the entire IPv4
> address space, is my understanding.  It is unlikely that a /64 will
> experience IP address scarcity.
>