IPv6 Addressing Help
nanog at daork.net
Wed Aug 19 16:36:12 CDT 2009
On 16/08/2009, at 1:29 AM, William Herrin wrote:
> Start with: /32
> Sparsely allocate 200 /56's
> Total remaining space: in excess of /33. In fact, you haven't consumed
> a single /48.
> Expandability by altering the netmask: to /40
> Largest allocation still possible: only /40
My suggestion was to sparsely allocate /48s to push addresses to POPs
(or something topologically relevant to your network, maybe even
NASes) as required.
So, 200 /56s, sparsely allocated, would still be one /48 (or however
many /48s you want to have around your network, as above).
Sparse allocation within each of those /48s is also potentially a good
idea - case by case. Doesn't make sense on an ADSL pool where everyone
has the same length. Makes sense where you're assigning address space
to customers who are likely to have different prefix lengths.
Sparse allocation of /48s within a /32 has the advantage of letting
you grow each area of your address space in each area independently.
You can put one /48 in one POP or NAS or something, and 10 in another,
without having to break any of your addressing architecture rules.
/48s seem flexible enough to me, but perhaps you want to use this
technique with /44s or /40s, or something.
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