IPv6: numbering of point-to-point-links

Jack Bates jbates at brightok.net
Mon Jan 24 07:44:39 CST 2011


On 1/24/2011 7:18 AM, bmanning at vacation.karoshi.com wrote:
> this results in -very- sparse matrix allocation - which is fine, as long as you believe that
> you'll never run out/make mistakes.  personally, i've use /126 for the past 12 years w/o any
> problems.
>

There isn't an increased mistake risk factor using /126 out of a /64 
assigned and your mistake factor probably slightly increases just 
assigning a bunch of /126 out of a single /64. We use /126 internal 
links, /128 loopbacks (these we do streamline), and customer links are 
generally /64, as currently we have no choice but use SLAAC + DHCPv6 
(thanks Cisco!).

That being said, while renumbering my network, I noted several link 
address mistakes. Had nothing to do with the /126 or /64 boundaries. I 
just left out one of the nibblet sets, and :: notation gladly makes that 
into a valid address. This leads me to believe that using short hand is 
likely to lead to more mistakes.


Jack




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