This counts downlink packets dropped because a paging ACL denied them; paging is the mechanism used to wake an idle mobile device before delivering downlink traffic, and the paging ACL decides which traffic is even allowed to trigger that wake-up. Packets counted here are downlink traffic the gateway decided was not important enough to page the device awake for, such as background chatter that would otherwise drain battery through unnecessary wake-ups. Repeated low-priority multicast traffic destined to an idle device would have those packets silently dropped here instead of paging the device awake each time.