Only the switch has it,

Each port of the switch has the function of automatically learning the address, and the source address (source MAC address, switch port number) of frames sent and received through the port will be stored in the address table. Aging time is a parameter that affects the learning process of switches. From the time when the address record is added to the address table, if each port does not receive a frame with the source address of the MAC address within the aging time, these addresses will be deleted from the dynamic forwarding address table (from the source MAC address, the destination MAC address and the port number of their corresponding switch). Static MAC address table is not affected by address aging time.