When you enable logging in a Security policy rule, the firewall generates a traffic log when traffic matches the criteria defined in the policy rule, and GTP logs for GTP session start and GTP session end for each mobile subscriber. All other logs for GTP traffic are event-based logs that are generated based on the options you enable on the GTP Protection Profile. For monitoring GTP traffic, the firewall uses the GTP logs to render a visual display on the Mobile Network Activity tab on the ACC, and gives you both predefined reports and the ability to generate custom reports.