The ones I've heard about is "people that are startup ISPs, and still too small for PA". So they get a PI (because that's all they can get), and when that's full, they get another PI, and so on, until they can demonstrate "utilization of a /21" - and then they go for PA.
They are effectively using PI as a "easier to get PA substitute" - which is wrong, but points at a serious problem in the policy.
If an end user needs between /24 and /21 and do not expect much growth within the next few years but would like to be able to easily change provider without renumbering then I believe PI space is a good solution. I do not see the reason for using PI space if you're an ISP intending to become LIR, this means you will need to renumber when you get your PA allocation no matter if you use PA or PI, so why not just get a PA assignment from your provider until you can justify the /21? Marcus Ruchti says that the majority of the ISPs will not announce PA space from another AS, does this include more specific announcements? If the community does not allow this, whats the point of this: 1. Why is PI space required rather than PA space? - If PI is requested for multi-homing please explain why the second provider cannot route PA space as a more specific route(with the PA block holder adding a more specific route too). (part of the questions which must be answered after applying for PI space). We set up a few customers requesting PI space, some of the bigger ones also set up BGP and gets their own AS, if they cannot justify (nor wishes) a PA allocation, they need to be able to get PI space. A very peculiar thing regarding policy, a customer of ours applied for a PA block but could not justify a /20 (a year ago), BUT, when we applied on their behalf for PA space (ours) we were allowed to assign them a /20....! I was then told that as they had now been assigned a /20 they would be allowed to become LIR...! Hopefully this was a misunderstanding, if not, I think this part of the policy might need a few changes.. Med venlig hilsen/Best regards Christian Rasmussen Hosting manager, jay.net a/s Smedeland 32, 2600 Glostrup, Denmark Email: noc@jay.net Personal email: chr@corp.jay.net Tlf./Phone: +45 3336 6300, Fax: +45 3336 6301 Produkter / Products: http://hosting.jay.net