IPv6 foot-dragging

Iljitsch van Beijnum iljitsch at muada.com
Fri May 13 07:56:54 UTC 2011

On 13 mei 2011, at 2:39, Jimmy Hess wrote:

> if the user starts obtaining
> multiple non-aggregable /48s  from different sources,  or obtains an
> additional PI allocation later, but
> keeps using the original /48.

Simple: make a rule that you don't get more than one PI block, and if you want a bigger one you have to return the old one. Oh wait, people use PI because they want to avoid renumbering? It was never meant for that. Maybe a good incentive to ask for the right size block in the first place.

The current RIR practice to reserve a /44 when a /44 is given out is a very bad one. It assures unfilterability, because now you have random sizes from /44 to /48 in the parts of the address space used for PI. And if say, 64k /48s are given out the space actually holds 1M /48s so if someone wants to blow up the IPv6 internet they can just start announcing a million /48s and our filters are powerless.

And that all in case a /48 isn't big enough (which is ridiculously rare in and of itself) to save ONE entry in the global routing table. So by trying to conserve the table we make it impossible to protect our routing tables.

> It is a heck of a lot better for network stability that any
> multi-homed user get a /32 PI,

No, that's completely ridiculous. It's like saying all flights should be flown with 747s just in case 10 football teams show up unexpectedly. That is, if a 747 could carry a million people (64k more than a small 16-seat plane).

Yes, the IPv6 address space is big but by giving people who need more than 65000 subnets a /32 so they can have 4000000000 subnets is unbelievably wasteful for no other reason than laziness.

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