IPv6 Prefix announcing

Tue Apr 26 17:12:40 UTC 2011

> From: Kate Gerry 
> Sent: Tuesday, April 26, 2011 9:39 AM
> To: 'Justin M. Streiner'; nanog at nanog.org
> Subject: RE: IPv6 Prefix announcing
> 
> Funny enough, some carriers actually require the 'smallest' as being
> /32... :(
> 

That might be true in PA space, but PI space is issued down to /48.  I
am not aware of anyone who filters smaller than a /32 in PI space though
that doesn't mean it doesn't happen.  The largest holdout was Verizon
but my understanding is they now accept a /48 in PI space.

So: 

A /32 is the smallest prefix issued in PA and some networks will not
accept a prefix smaller than /32 from PA address space.
A /48 is the smallest prefix issued in PI and some networks will not
accept a prefix smaller than /48 from PI address space.

In other words, if you are going to attempt to multihome a /48
allocation from your provider's aggregate, you are better off getting
your own provider independent block.