Allocation and assign do have definitions - could these be improved to clarify the meaning? Or does 'delegate' simply convey a much clearer intention with the address space?

Delegation is clearer for two reasons. Firstly, it implies that the the delegator is passing on some responsibility for the address space. The organization receiving a delegation is responsible for managing and administering the addresses. In the case of an assignment, this is less true. For instance, ISPs regularly reassign addresses after a customer disconnects and everyone seems to understand that addresses assignments are controlled by the assigner and can be withdrawn. The second reason has more to do with psychology. Because the terms "allocation" and "assignment" are similar in meaning and visually similar, they are easily confused by a lot of people. They both begin with "a" followed by a double consonant and end with a latin suffix. Of course, clear definitions are always a good thing as well. Michael Dillon Network Product Engineering Radianz