IPv6 foot-dragging

Jimmy Hess mysidia at gmail.com
Fri May 13 00:39:35 UTC 2011

On Thu, May 12, 2011 at 5:49 PM, George Bonser <gbonser at 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

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.


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