Subject: Re: [RRG] Renumbering...

From: Iljitsch van Beijnum <[email-masked]>
Date: Tue, 16 Sep 2008 11:03:35 +0200

On 5 sep 2008, at 18:58, Stephen Sprunk wrote:

>> The users leaned on the RIRs to do
>> PI, and any attempt to get rid of PI would take even more ooomph than
>> stopping them, and there clearly wasn't enough for that.

> Speaking as one of "them", the reason we proposed (and accepted)  
> PIv6 was that the IETF had provided no acceptable (to us) alternative.

That is nonsense. The shim6 effort was well under way at that point  
but not yet mature enough that it was possible to know whether it  
would solve the problem. So even if you are of the opinion that shim6  
isn't an acceptable solution, at the point the decision was made this  
was still unknowable and thus the decision was wrong.

(And the fact that this decision is made by random people in one part  
of the world rather than by the IETF or some other world wide  
organization with at least _some_ technical props shows how broken the  
RIR policy development system is.)

> We understand the costs of PI space,

No we don't.

> If there were a viable alternative

Easy: increased stretch routing. Bring the packets to the place where  
the routing info is (in aggregated form, of course) rather than the  
other way around. This of course means that if 199/8 is used in  
Seattle, Montreal, Tokyo and Cape Town, and the router that knows the  
more specifics for 199/8 is in Tokyo, two people using 199/8 addresses  
in Seattle and Montreal aren't going to be very happy because their  
packets flow through Tokyo. But that's just an incentive to renumber.

There are of course technical challenges with any new approach but  
those can be sorted out fairly easily. The only real issue is  
accepting the consequences. Something people don't like to do.

> PIv6 blocks plus substantial reservations for growth

Reservations don't work, they just break our ability to filter the  
routing table without buying us anything useful.

> 2. A fixed and well-known minimum block size means filtering more- 
> specifics is easier.

Except that ARIN reserves /44s for the PI /48s it gives out so they  
burn through space as if they're giving out /44s but they allow for as  
many prefixes as if they're giving out /48s. I.e., for 64k PI prefixes  
they need a /28 but if someone deaggregates that /28 into /48s it's 1M  
prefixes. 64k extra prefixes is probably doable for a current router  
but 1M isn't so this practice means there can't be any protection  
against deaggregation in routers.

> I think the problem was being _too_ hard-nosed and refusing to  
> listen when the target audience for solutions was saying, preferring  
> to push an "everyone must use PA" dogma.

Actually ARIN has removed the problem. By allowing PI they've said  
that PI isn't a problem so basically we don't need the RRG effort.

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