[ppml] Definition of "Existing Known ISP"

[michael.dillon at bt.com]

> I personally think it's unfortunate the policy manual uses the term
> ISP, because it is misleading.  I don't have a better one to suggest
> though.

The rest of the world uses the term, LIR, something which is totally
meaningless and therefore could be precisely and unambiguously defined
by the RIRs. Note that ARIN uses the term LIR in the IPv6 policy. Local
Internet Registry has a vague whiff of an org that gets IP addresses and
gives them to others, but only to those who already understand RIR
stuff.

The big question is, do all occurences of the term "ISP" in ARIN's
policy and other documents, actually refer to the narrow definition of
an LIR, or is ARIN also sometimes using the term with other contexts in
mind.

--Michael Dillon