What is BCP re De-Aggregation: strict filtering /48s out of /32 RIR minimums.

Wed Nov 14 13:10:57 UTC 2012

Hi,

I am hoping for a bit of advice.  We are rolling out IPv6 en mass now to peers and I am finding that our "strict" IPv6 ingress prefix filter is meaning a lot of peers are sending me zero prefixes.  Upon investigation I determine they have de-agregrated their /32 for routing reasons / non interconnected islands of address space and in consequence advertise no covering /32 route.  The RIR block that the allocation is from is meant to have a minimum assignment of /32.

From:

http://www.space.net/~gert/RIPE/ipv6-filters.html

We get:

ipv6 prefix-list ipv6-ebgp-strict deny   3ffe::/16 le 128
ipv6 prefix-list ipv6-ebgp-strict permit 2001:500::/30 ge 48 le 48
ipv6 prefix-list ipv6-ebgp-strict deny   2001:db8::/32 le 128
ipv6 prefix-list ipv6-ebgp-strict permit 2001::/32
ipv6 prefix-list ipv6-ebgp-strict permit 2001::/16 ge 35 le 35
ipv6 prefix-list ipv6-ebgp-strict permit 2001::/16 ge 19 le 32
ipv6 prefix-list ipv6-ebgp-strict permit 2001:0678::/29 le 48
ipv6 prefix-list ipv6-ebgp-strict permit 2001:0c00::/23 ge 48 le 48
ipv6 prefix-list ipv6-ebgp-strict permit 2001:13c7:6000::/36 le 48
ipv6 prefix-list ipv6-ebgp-strict permit 2001:13c7:7000::/36 le 48
ipv6 prefix-list ipv6-ebgp-strict permit 2001:43f8::/29 ge 40 le 48
ipv6 prefix-list ipv6-ebgp-strict permit 2002::/16
ipv6 prefix-list ipv6-ebgp-strict permit 2003::/16 ge 19 le 32
ipv6 prefix-list ipv6-ebgp-strict permit 2400::/12 ge 19 le 32
ipv6 prefix-list ipv6-ebgp-strict permit 2600::/12 ge 19 le 32
ipv6 prefix-list ipv6-ebgp-strict permit 2610::/23 ge 24 le 32
ipv6 prefix-list ipv6-ebgp-strict permit 2620::/23 ge 40 le 48
ipv6 prefix-list ipv6-ebgp-strict permit 2800::/12 ge 19 le 32
ipv6 prefix-list ipv6-ebgp-strict permit 2a00::/12 ge 19 le 32
ipv6 prefix-list ipv6-ebgp-strict permit 2801:0000::/24 le 48
ipv6 prefix-list ipv6-ebgp-strict permit 2c00::/12 ge 19 le 32
ipv6 prefix-list ipv6-ebgp-strict deny 0::/0 le 128

I have peers in 2a00::/12 that are advertising me /48s without the /32 assigned to them.

While this has been a problem in IPv4 land in the past with some people de-aggregating a /19 to regional /24s with no covering route because of no backbone.  What should we be doing in IPv6 land as I suspect this may become a bigger problem than it ever was in IPv4.

I can adopt the view, well you should, so I'm going to filter, and they can say well that's not practical, we have a /32 and we advertise a /48 at each individual internet exchange.  RIRs policy wont allocate us a lot of separate /48s from an appropriate block.  Aggregation argues you shouldn't de-aggregate.

We might as well start off as we mean to go along and try not to pollute the v6 route table with all the rubbish that is in the v4 one.

So what is the "best" answer.

1>     Don't advertise islands of space under assignment minimum, without providing a covering aggregate route?

2>     Don't use strict filters, they don't work well and de-agragegation with IPv6 is going to be a problem?

3>     Don't use filters, generate it from an IRR?

Given there is no "right" answer what is considered to be the best fit one?

Kind Regards

Ben