Re: graceful renumbering of CPE networks

[Michael Richardson <[e-mail]>]

Brian E Carpenter <[e-mail]> wrote:
    mcr> results in flash renumbering.  There is no apparent way to introduce
    mcr> a new prefix while the old prefix is still alive.

    > Whereas of course RFC 4192 specifically describes planned renumbering
    > (for enterprise network networks with actual humans in charge.)
    > However, it seems to me that RFC 7084 is aimed mainly at manager-free
    > scenarios. I do agree that a document on manager-free renumbering
    > might be appropriate, but I think it's more than a simple fix to 7084.

Let's talk about this.

I think that the problem is seperable into the ISP<->CPE protocol,
and the CPE<->network protocol.  I think that RFC4192 provides for
the second part very well.

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.
Probably such a thing could be simulated by adjustment of T1 and T2 timers
in DHCP-PD, forcing the CPE to come back to confirm the old address, and at
that point, adding the new prefix.  This may require new specification as
well as new code; those parts of DHCP are not in my brain cache right now.

    > Mumble HNCP mumble. RFC 7788 doesn't really seem to tackle the issues
    > we've been discussing here.

I guess that you are saying that section 6 of 7788 doesn't say enough here?
It seems that if the new prefix is available prior to the lifetime of the old
prefix expiring, that it can be done smoothly.

--
Michael Richardson <[e-mail]>, Sandelman Software Works
 -= IPv6 IoT consulting =-