IPv6 routing /48s

Joe Abley jabley at hopcount.ca
Mon Nov 17 23:47:44 UTC 2008

On 2008-11-17, at 17:46, Robert.E.VanOrmer at frb.gov wrote:

> Are there any parties out there routing /48 IPv6 networks globally?

Yes. Some particularly visible examples are root and TLD server  
operators. There are some TLDs which are well-served by IPv6-capable  
nameservers, but which would be completely invisible to v6-only  
clients if their covering /48s were not accepted.

ASes which refuse prefixes longer than 32 bits across the board as a  
matter of policy are broken.

The last time I looked, the RIRs with v6 micro-assignment policies  
were all doing long-prefix assignments from an easy-to-identify range  
of addresses. Creating a general-purpose filter which lets through PI / 
48s but drops PA/deaggregated /48s is not rocket science.

> I ran
> into a supposed Catch-22 with Verizon and IPv6 address space and was
> looking for clarification.

I was once told by another large carrier I was trying to buy from in  
Miami that "you are not allowed to announce your own addresses in  
IPv6; you have to use addresses from your upstream".

While the goal of encouraging use of PA addresses and discouraging  
deaggregation may be noble and good, it seems more education is  
required in some areas. "There is such a thing as PI in IPv6", for  
example, and perhaps "just because it's a /48 doesn't mean it's not PI".


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