[ppml] Big numbers

Leo Bicknell bicknell at ufp.org
Wed Apr 9 15:03:29 EDT 2003

In a message written on Wed, Apr 09, 2003 at 02:55:34PM -0400, Marshall Eubanks wrote:
> I thought that the rightmost 64 bits were supposed to be used to store 
> the
> MAC address and related info, so a /64 is like a IPv4 /32 ?

Much of the IPv6 documentation talks this way.  On my employer's
test network we are using a /64 broken into /126's for point to
point links with no issues.  Works great.  I've also set up unix
servers with static addresses (rather than doing autodiscovery) on
things like /120's, works great with the code I've tested as well.

So, it would appear forwarding code treats it as a full /128 bit
space, and the only things assuming the lower /64 bits are special
are things that adhere to other standards (autodiscovery, mac
encoded in the address, etc).

It's still unclear to me how IPv6 will really be used.  The ISP's
that I see experimenting with IPv6 are largely treating it the same
way as IPv4.  Yes, there are are bigger addresses, and the bogon
list is different and all that, but really it's IPv4 with bigger
addresses from an ISP point of view.  Sure, people may filter peers
on a /48 or something like that (all that's still up in the air
too, best I can tell), but that's no different than the IPv4 ad-hoc
situation that developed.

       Leo Bicknell - bicknell at ufp.org - CCIE 3440
        PGP keys at http://www.ufp.org/~bicknell/
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