IPv6 Address Planning

Wed Aug 10 16:03:00 UTC 2005

In a message written on Wed, Aug 10, 2005 at 03:55:32PM +0100, sdb at stewartb.com wrote:
> The current recommendation for a /48 for any customer (pretty much) does
> initially seem to me to be a bit wasteful, though that's perhaps because I
> keep thinking in IPv4 terms.  Having said that, I think that perhaps a /48
> for home users isn't _really_ necessary.  How many domestic appliances can
> you connect to the net :)

That's not really the question you want to be asking.  The current
mantra is a /64 per subnet.  Now, we can argue that point separately,
but taking that as a given for now (so autoconfiguration will work)
what a /48 is really telling you is that a home user gets 65536
subnets.

IPv6 allocations in the host portion (with /64 boundaries) are
sparce, even for the largest networks.  The number of hosts becomes
unimportant.  The question we need to ask is how many independant
subnets will they need.

This is why many people are proposing a /56 for home users, as it
gives you 256 subnets.  Still more than most people will need.

Others have proposed /52 and /60, since many want to claim DNS is
easier if done in nibbles.

-- 
       Leo Bicknell - bicknell at ufp.org - CCIE 3440
        PGP keys at http://www.ufp.org/~bicknell/
Read TMBG List - tmbg-list-request at tmbg.org, www.tmbg.org
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