v6 & DSL / Cable modems

Iljitsch van Beijnum iljitsch at muada.com
Fri Feb 6 15:14:33 UTC 2009

On 6 feb 2009, at 16:02, Joe Loiacono wrote:

>> Given that ARIN at least is assigning end-user /48s out of 2620::/23
>> it would be useful to accept these announcements. If not end-user PI
>> is dead in the water. Some providers might like that. End-users
>> probably won't.

> That range alone is 25 bits of routing, equivalent to routing all  
> the way
> down to /25s in the IPv4 world. But I don't see how you could route  
> some
> /48s without having software to route all /48s and that is  
> hugemongous.
> And then times 4 for 128 bits. But, I'm not a routing engine guy, so  
> I'm
> probably missing something ...

The problem is that ARIN reserves a /44 for every /48 they give out.  
So that means the most you'll see out of that /23 is 2M prefixes (I  
don't think there are many routers out there that can handle a v6  
table this large) but since you need to accept /48s, this could be  
deaggregated into 32M prefixes.

The RIRs need to stop this reservation stuff, it makes prefix length  
filtering impossible.

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