On Sat, 16 Jun 2001, David R Huberman wrote:
Either you're saying it wrong (writing it wrong, as it were) or you are misunderstanding RFC2050.
ISPs *should* request 80% utilization of a block assigned to an end-user prior to assigning additional address space.
You understand that, right?
On Sat, 16 Jun 2001 up@3.am wrote:
It's not really a question of what makes sense, it's what you need to do to keep ARIN happy. As an ISP, if you only apply the 25% / 50% rule to your customers, how are you supposed to demonstrate 80% utilization to ARIN when requesting any kind of allocation?
If you've handed out a whole bunch of /24 - /29 subnets to your customers and they are compliant with RFC2050, this could well result in a situation where you've depleted nearly all of your address space, yet are nowhere near 80% utilization or your, say, /21 from your upstream. Is ARIN going to allocate you a /20?
David: Sorry, but nope, I don't understand it that way. Perhaps we need to properly define utilization. To an ISP, this means assignment of address space via SWIP to customers. ARIN wants you to have "assigned" 80% of your address space before asking for another allocation. To an end user, it means active hosts. ARIN suggests following RFC2050 and the 25%/50% standard prior to receiving an additional address assignment from their ISP. You, the ISP, are obligated to have justification using RFC2050 as the standard for assignements to your customers. ARIN requires you to have assigned 80% of your allocation to those customers prior to receiving additional allocations and may want to review the justification you've received from your customers. So, yes, it's very likely that when you have assigned 80% of your allocation, the sum of all your customer's utilization may be something like 50%. Judging from the confusion on this issue, I'm not surprised that some customers have a hard time getting assignments from their ISP's. This is even more confusing when the customer is both an end user and a downstream ISP themselves. In that case, it may make sence to consider the address space they use themselves as a separate assignment from them to themselves. That way you can properly determine when they have reached 80% assgnment of their space. If they aren't in turn assigning address space, then they are simply an end user and should be following RFC2050. Does this all make sence? Chuck