How it is counted. A collector subscribes to each broker's gateway stats reports (every 30 seconds per gateway),
the retained connection state, and the broker's own system metrics. It keeps one row of totals per broker per minute, for 90 days.
Uplinks come from the counters inside each gateway's stats report, so the collector never has to receive the uplinks themselves.
Availability is the share of minutes in which the collector was connected and receiving.
What is not here. No gateway IDs, IP addresses, locations or payloads are stored or shown. Gateway IDs are held in memory
only long enough to count distinct gateways.