Internet Edge Router replacement - IPv6 route tablesizeconsiderations

Owen DeLong owen at delong.com
Fri Mar 11 01:33:51 CST 2011


On Mar 10, 2011, at 11:22 PM, Dobbins, Roland wrote:

> 
> On Mar 11, 2011, at 2:02 PM, Owen DeLong wrote:
> 
>> If you want to be truly anal about it, you can also block packets to non-existent
>> addresses on the PtoP links.
> 
> Sure, I advocate iACLs to block traffic to p2p links and loopbacks.  Still, it's best not to turn routers into sinkholes in the first place.
> 
>> This isn't a one-time-use of IPv6 addresses and the one-time-uses of IPv6 addresses are what should be considered unscalable and absurdly wasteful.
> 
> I don't know that I agree with this - I can see lots of value in one-time-use addresses/blocks, and have a metaphysical degree of certitude that they'll be used that way in some cases, irrespective of what I think.
> 
If so, opefully from a tiny and limited range. fc::/7 sounds good to me. It has few other useful purposes in life.


>> There's a lot to be said for the principle of least surprise and uniform /64s actually help with that quite a bit.
> 
> Enforcing uniformity of wasteful and potentially harmful addressing practices in the name of consistency isn't necessarily a win, IMHO.
> 
We can agree to disagree. I don't think it's so wasteful and it's what the bits were put there to do.

Perverting them to other uses and then complaining that the legitimate uses are getting in the way,
OTOH, well...

> ;>
> 
>> Frankly, unless you have parallel links, there isn't a definite need to even number PtoP links for IPv6.
>> Every thing you need to do with an interface specific address on a PtoP link can be done with link local.
> 
> Which is why IP unnumbered caught on so well in IPv4-land, heh?
> 
There's a HUGE difference between IP unnumbered and link-local.

Frankly, absent parallel links, there was a lot to be said for IP unnumbered
and I think that if people had better understood the implications of where and
when it was a good vs. bad idea and tied it properly to loopbacks instead
of $RANDOM_INTERFACE, it might have caught on better.

Owen





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