On Thu, May 12, 2011 at 5:49 PM, George Bonser <gbonser@seven.com> wrote:
Possibly the hit might be the same, but possibly not. An organization that requires a second /48 from their upstream might get one that can't be aggregated with the previous one. It is my understanding that ARIN
A very important distinction. The _immediate_ hit to the DFZ might be the same as obtaining PI V6 space, but the _long term_ hit to the DFZ might be much greater; particularly if the user starts obtaining multiple non-aggregable /48s from different sources, or obtains an additional PI allocation later, but keeps using the original /48. It is a heck of a lot better for network stability that any multi-homed user get a /32 PI, and find that they will never need more than a /48 of it, than it is to try to "conserve" address bits, and require the multi-homed user stick it out with a /48. With IPv6, bits for addressing networks are not scarce (like they were with IPv4), but more importantly, router FIB bits _are_ scarcer. With IPv4, we face the certainty of address bit assignment exhaustion. With IPv6, we face a greater risk of address bit _router_ assignment exhaustion. Because every IPv6 address has 4x as many bits as an IPv4 address. And a /48 prefix has consumes at least 2x as many bits as a /24 prefix. -- -JH