Preseem is very flexible and can be integrated with most billing systems. This includes integrating with home-grown billing systems. If it's one commonly used by WISPs, chances are good that we are already working on it. Just ask us!
Preseem maps information as metadata attached to your customers' traffic IP addresses. Here is the typical information we require to perform subscriber mappings:
Subscriber ID, name, plan speeds, and some key that we can use to map their IP address to their ID - typically CPE MAC or subscriber ID itself.
This set of information may somewhat depend on your network architecture. A spreadsheet can be used to store this information, where each row contains one data point per column mentioned above.