Spent quite a few hours today doing debugging on the Mock CMTS code, in the end, it was all bugs in the shims that short-circuit around TwistedSNMP for the testing environment, but I spent far too long spelunking through the code on either side of it (the ping-scanner, which has been running for months, and TwistedSNMP, which has been stable for even longer).

Moral of the story; if something has worked fine everywhere else, and you've subclassed it, but now you get errors, you've probably messed up in your subclassing.

Upshot is that the demo now properly finds all 1500 modems on the 3 CMTS's. Next task is to make sure the physical-group stuff works.