Difference between Primary and Secondary monitoring locations
Primary location is the main location from which your configured monitors are polled according to your poll interval settings. If a website is reported as down when polled from a primary location, Site24x7 will verify the status from the configured secondary locations before sending a downtime notification.
For instance, if a website is detected as down from L1 (Primary location), Site24x7 will also check from L2 and L3 (Secondary locations as configured by the user) and send notification only when the website is detected down at both the locations.