IPv6 PI block is announced - update your filters 2620:0000::/23

Jeroen Massar jeroen at unfix.org
Thu Sep 14 17:56:05 CEST 2006

Stephen Sprunk wrote:
> Thus spake "Jeroen Massar" <jeroen at unfix.org>
>> 8<-----------------------------------------
>> IPv6 Assignment Blocks   CIDR Block
>> 2620:0000:/23
>> ----------------------------------------->8
>> Expect blocks in between /40 and /48 there.
> Expect mostly /48s and /44s, given that ARIN has not defined any 
> criteria for what justifies more than a /48.

The first three are already available:
2620::/48     - U.S. Securities & Exchange Commission
2620:0:10:/48 - S. D. Warren Services Co.
2620:0:20:/48 - CollabNet

These have been added to GRH (http://www.sixxs.net/tools/grh/) now lets 
see how long it takes for them to show up in the global tables and how 
far their reach will be. Hallway talk: one of them was requested 6 sept, 
answer on the same day that it will be issued, received on 13 sept, nice 
work there ARIN :)

 > Of course, some folks will
 > announce a /44 instead since the block is reserved, but it should
 > still only be one route.

That it is reserved as a /44 doesn't mean one can announce that /48 as 
it is not assigned to them.

> Still, even if every org that qualified for an assignment today got one, 
> you're still only looking at a couple tens of thousands of routes max. 
> ARIN using a /23 for PIv6 is either serious overkill or "we'll never 
> need to allocate another block" at work.

The /23 is a good thing indeed, people won't most likely have to ever 
update their filters for that one.

> IMHO, BGP will fall over and die long before we get to that many ASNs.

I guess that will indeed be the case.

> Remember, the goal in giving people really big v6 blocks, vs. IPv4-style 
> multiple allocations/assignments, is to reduce the necessary number of 
> routes to (roughly) the number of ASNs.

But people require Traffic Engineering, as such they might want to do 
some routing tricks and thus split up their /48. Only the future will tell.

> If PIv6 folks start announcing absurd numbers of routes within their 
> allocation, I'd expect ISPs to start filtering everything longer than 
> /48 -- if they don't do so from the start.

Most ISP's already do this now. In effect /19 - /48 is unfiltered in 
most places.


PS: Anybody knows when ARIN will finally learn CIDR? :)

$ whois -h whois.arin.net 2620::/48

CIDR queries are not accepted

No match found for 2620::/48.

They clearly understand it is CIDR and the resulting record even has a 
CIDR field; they really should move to the RPSL based db that RIPE provides.

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