filtering /48 is going to be necessary

Sat Mar 10 06:02:00 UTC 2012

> I'll put this as bluntly and succinctly as I can because I find the LIR
> distriction arbitrary...
> 
> I have an ipv6 direct assignment from ARIN.

I am assuming you are an enterprise in PI space and not an ISP in PA space?

> It is sized to meet the needs of my enterprise consistent with needs
> for future growth number of pops, prevailing ARIN policy etc.
> 
> Because my network is discontiguous I must announce more specific
> routes than the assignment in order to reflect the topology I have both
> in IPV4 and in IPV6.

> I fully expect (and have no evidence to the contrary) that my transit
> providers will accept the deaggreated prefixes and that their upstreams
> and peers will by-in-large do likewise.

If you are in PI space, I believe most people take down to a /48 as a /48 is generally accepted to be a single "site".  So let's say you were given a /40 and have several disconnected sites.  Most people are going to accept a /48 from you in PI space. I would say pretty close to "everyone" is going to accept a /48 from PI space.

An ISP that has been given a /32 or larger allocation from PA space and might have 10,000 customers each assigned their own /48 could instantly more than double the size of the IPv6 routing table if they disaggregated that /32.  

The problem here is that each /32 is 65536 /48 networks.  An even larger net, say a /30 that disaggregates due to a router configuration goof means a potential of a huge number of networks suddenly flooding the Internet.