Internet Edge Router replacement - IPv6 route tablesizeconsiderations

Leo Bicknell bicknell at
Fri Mar 11 18:56:49 CST 2011

In a message written on Fri, Mar 11, 2011 at 04:13:13PM -0800, Owen DeLong wrote:
> On Mar 11, 2011, at 10:58 AM, Leo Bicknell wrote:
> > Well, I at least think an option should be a /80, using the 48 bits
> > of MAC directly.  This generates exactly the same collision potential
> > as today we have with a /64 and an EUI-64 constructed from an EUI-48
> > ethernet address.  The router is already sending RA's for SLAAC to
> > work, sending along one of a well-known set of masks would be a
> > relatively minor modification.
> > 
> How would you use that on a Firewire netowrk or FDDI or any of the
> other media that uses 64-bit MAC addresses?

It wouldn't.

I'm not proposing a solution for everything, just a useful case for
some things.  I don't want to change say, RIR policy that you can
allocate a /64, just allow operators to use /80's, or /96's in a
more useful way if they find that useful.

Basically I think the IETF and IPv6 propoents went a bit too far
down the "one size fits all" route.  It has nothing to do with how
many numbers may or may not be used, but everything to do with the
fact that you often have to fit inside what's been given to you.
If you're stuck with a monopoly provider who gives you a /64 to
your cable modem there should be easy options to split it up and
get some subnets.

       Leo Bicknell - bicknell at - CCIE 3440
        PGP keys at
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