URL for PURL Server
An interim URL for the IEEE PURL Server will be fine to start, but an optimum URL should be the goal.
I suggest something like purl-ieee.org with extensions of purl-ieee.org/cco.
PURL Servers need to assure developers of long-term stability, so using the IEEE name will help project this.
However, the initial version of the PURL Server should not be delayed awaiting approval of an optimal URL.