[ppml] Policy regarding subnets smaller than /64

Scott Leibrand sleibrand at internap.com
Fri Nov 16 16:15:47 EST 2007

Brian Dickson wrote:
> The problem I'm illustrating is the hammer/nail problem.
> If it is not *possible* to do any kind of bit-mapped plan, then we are 
> not supporting those who *might* choose to (or need to) do so.

Ok.  I'm not opposed to allowing the use of subnets longer/smaller than 
/64, although I do oppose your earlier policy proposal to encourage it 
via ARIN guidelines.

> This is neither about encouraging, nor about requiring, a particular 
> plan. It is about *allowing* it, by providing the essential tools to 
> support it.
> The only tool needed, currently, is the ability to register 
> allocations >/64 - something I perceive the current policy to 
> prohibit. (And now we stray into discussions about policy, rather than 
> about the use cases.)

Ok, let's discuss the policy then, as this is the public policy mailing 
list.  :-)

IMO it's entirely appropriate to use subnets smaller/longer than /64 for 
certain use cases, like the one you outlined.  I do not believe it is 
appropriate to allocate anything smaller/longer than a /64 to a 
downstream customer, as doing so limits their ability to grow as 
needed.  In order to support your subnetting scheme, I believe an LIR 
should reassign an appropriately sized netblock (/64, /56, or /48), and 
the recipient network should subnet that assignment as needed to support 
their need for variably-sized subnets.  If they don't need an entire 
/64, then they can reserve the rest of it for future growth.

What other "essential tools" do you believe are missing from current policy?


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