Comment 9 for bug 1543094

I like the idea of computing availability on the fly and not storing the availability. After taking a stab at a solution, the drawback I'm finding is that there are a large number of unit tests (100+) that assume a very deterministic way of allocating IP addresses, and those are just the tests I've found. What Carl is proposing would introduce an algorithm for selecting an IP address to allocate that isn't deterministic at all. I'm not suggesting that tests be the gating factor as to whether we pursue this approach, I'm simply pointing out a substantial amount of churn. As I work through this, I'm also finding it hard to use test failures as a guide for which tests to re-work as this non-deterministic behavior manifests itself in non-deterministic pass/fail of certain tests from run-to-run. We should proceed with an abundance of caution if we take Carl's approach, even if it does yield positive results in the end.