IPv6 multihoming

[Bernhard Schmidt]

On 05.02.2011 14:52, Bernd Walter wrote:

Hi,

>>> If you mean that punching holes in PA blocks is a bad idea, I agree,
>>> but really only for the same reason - it doesn't scale to millions,
>>> only to thousands. Once people accept /48s, PI or PA are just about
>>> the same.
>>
>> I don't agree. A lot of /48s in PA space look like unintentionally
>> leaked more-specifics from iBGP, while a /48 from PI space is usually
>> intentional.
>>
>> Which is why I'm (of course) accepting /48 from PI+IXP ranges but not
>> only up to /36 from PA.
>
> So multihoming a /48 PA or allow another ISP to announce it during
> transition phase is already considered bad practice?

This is a very controversial topic. If you need to do it this way it is 
enough that the old ISP sees the more-specific.

> You differentiate PI from PA space by using RIR databases?

No, all RIRs make their assignments from dedicated blocks. Here is my 
filter:

!
! Documentation prefix
ipv6 prefix-list ISP-fulltable-in seq 5 deny 2001:DB8::/32 le 128
!
! ARIN Microallocations
ipv6 prefix-list ISP-fulltable-in seq 100 permit 2001:500::/30 ge 40 le 48
ipv6 prefix-list ISP-fulltable-in seq 105 permit 2001:504::/30 ge 48 le 48
! ARIN IPv6-PI
ipv6 prefix-list ISP-fulltable-in seq 110 permit 2620::/23 ge 40 le 48
!
! RIPE Microallocations
ipv6 prefix-list ISP-fulltable-in seq 200 permit 2001:678::/29 ge 40 le 48
! RIPE IXP
ipv6 prefix-list ISP-fulltable-in seq 205 permit 2001:7F8::/32 ge 48 le 48
!
! APNIC IXP
ipv6 prefix-list ISP-fulltable-in seq 250 permit 2001:7FA::/32 ge 48 le 48
! APNIC portable assignments (http://www.apnic.net/db/min-alloc.html)
ipv6 prefix-list ISP-fulltable-in seq 255 permit 2001:C00::/23 ge 40 le 48
!
! AfriNIC PI
ipv6 prefix-list ISP-fulltable-in seq 270 permit 2001:43F8::/29 ge 40 le 48
!
! LACNIC IXP and Critical Infrastructure 
(http://www.lacnic.net/en/registro/)
ipv6 prefix-list ISP-fulltable-in seq 280 permit 2001:13c7:6000::/35 ge 
40 le 48
! LACNIC PI
ipv6 prefix-list ISP-fulltable-in seq 285 permit 2801::/24 ge 40 le 48
!
! 6to4 Anycast Prefix
ipv6 prefix-list ISP-fulltable-in seq 300 permit 2002::/16
ipv6 prefix-list ISP-fulltable-in seq 305 deny 2002::/16 le 128
!
ipv6 prefix-list ISP-fulltable-in seq 990 permit 2000::/3 ge 12 le 36
ipv6 prefix-list ISP-fulltable-in seq 1000 deny ::/0 le 128

But as I said, a very controversial topic. In my eyes we should make 
sure to avoid the roating table bloat today and maybe relax the rules 
later if necessary. Others say it should be as easy and similar to IPv4 
as possible to help migration.

I'm not against more-specifics from PA per se, but as long as there are 
networks that continue to leak dozens of more-specifics and don't do 
anything about it I don't see a way forward. If there is a way to limit 
it, great.

Bernhard