IPv6 PI allocation

Kevin Loch kloch at kl.net
Thu May 17 20:27:25 CEST 2007

Colm MacCarthaigh wrote:

> Right now, the use of /127's and /126's for link address by some
> networks are a bigger part of future problems than anything represented
> by PI.

Are you suggesting that routers should not route all 128 bits?  If
we are going to use 128 bit addresses then we need to be able
to route all 128 bits in silicon.  I'm sure you have a few /32 IPv4
static routes in your tables from time to time...

I prefer /112 as a default size for links because:
- It is an ideal boundary for record keeping and visual identification
   of subnets (unlike /126 or /127)
- It's large enough to support multiple devices for varying applications
   and/or reconfiguration/migration on ethernet type links
- /64 is just an insane waste of addresses (or subnets if you look at it
   that way).

I do use /64 for subnets that hosts occupy, mainly to make autoconfig
possible if it is ever desired.

- Kevin

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