Re: Using /126 for IPv6 router links

[Glen Turner <gdt () gdt id au>]

On 24/01/10 12:54, Owen DeLong wrote:
> Use the /64... It's OK... IPv6 was designed with that in mind.

I'd suggest using a /126. For two reasons.

1) Using EUI-64 addresses on router-router links is an error, the
   consequences of which you encounter the first time you replace
   some faulty hardware.[1]  I have made this error :-(  If you
   are not using EUI-64 then assigning a non-autoconf /64 is no
   less or more work than assigning a non-autoconf /126.

2) Having a block of addresses for router-router links (and other blocks
   for other infrastructure such as loopbacks and unicast) makes ACLs
   much simpler. Using a /126 means that this block can last for a long,
   long time, reducing configuration maintenance.

Cheers, Glen

[1] Basically, interface addresses end up scattered through the
    router's configuration (some manufacturers are better than
    others in this regard). Tracking down all the references to
    an address and changing the config merely as the result of a
    hardware swap is painful and adds complexity at a time when
    it is not desired.

--
 Glen Turner  <http://www.gdt.id.au/~gdt/>
 Network Engineer
 Australia's Academic & Research Network  <http://www.aarnet.edu.au/>