filtering /48 is going to be necessary

Owen DeLong owen at
Sat Mar 10 18:42:37 CST 2012

On Mar 10, 2012, at 6:08 AM, Jimmy Hess wrote:

> On Sat, Mar 10, 2012 at 12:52 AM, George Bonser <gbonser at> wrote:
>>> I'm well into my second decade of having a v6 prefix in the dfz and am
>>> passingly familiar with powers of two...
>> Point is that expecting people globally to take a /48 from PA space probably isn't a realistic expectation.
> Exactly....
> What's more realistic is you have to get a single /48 of PI space for
> people to carry that globally.

I fail to understand what difference it makes to a router whether a /48 is from PA or PI.

> And if you have 5 discontiguous networks, what the RIRs should do is
> carve a /44 out for your
> present and future PI allocations   and issue you    the  8  /48s;

Well, they carve out a /44 and issue you the /44 in most cases that I am aware of. Is that a problem?
If so, why? Seems rather silly.

> the PI /48 routing slots
> that you have justified need for --  arranged so that they fall within
> the same /45.

RIRs don't issue routing slots. They issue addressing blocks. Usually (though not always) these addressing blocks are aligned with prefixes.

Sometimes those prefixes end up in one routing slot. Sometimes more. Occasionally, none at all.

There is no definite relationship between network blocks issued by RIRs and prefixes and even less so between prefixes and routing slots.


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