A network processing unit includes a first table, a forwarding table, and a processor. The first table includes a first entry for a network, including a network aging, which includes the network processing unit. The forwarding table includes a second entry associated with a network entity which includes an indication of whether network traffic associated with the entity has been encountered in the current or previous network aging period. The processor is configured to receive an indication from a hardware timer that a hardware aging cycle has ended, and then determine whether the network aging period has ended. If so, the processor is configured to determine for a first network entity in the forwarding table whether traffic associated with the entity has been encountered in the current or previous network aging period. If not, then the processor is configured to remove the given first network entity from the forwarding table.