This object defines the switching mode in which this port operates. The switching mode of a port determines whether or not it learns station location information from source addresses of packets received on the port; the switching mode also determines whether or not packets with unknown destination addresses received on other ports are flooded out this port. The following notation is used in the switching mode definitions that follow: LRN: station location information is learned from source addresses of packets received on port. !LRN: station location information is NOT learned from source addresses of packets received on port. FUD: packets with unknown destination addresses received on other ports are flooded out this port. !FUD: packets with unknown destination addresses received on other ports are NOT flooded out this port. A port may be configured to operate in one of the following switching modes: standard(1): LRN & FUD This is the mode in which all ports of a 802.1D-compliant standard switch operates. workgroup(2): LRN & !FUD This is the mode in which workgroup side ports of a workgroup switch operates. backbone(3): !LRN & FUD This is the mode in which the backbone port of a workgroup switch operates. manual(4): !LRN & !FUD In this mode, forwarding out this port is fully determined by management-specified filters. When learning is disabled on a port (i.e., mode is changed to backbone(3) or manual(4)), whether addresses previously learned on the port are purged immediately or allowed to age out naturally is implementation dependent. Note that all ports may be configured to operate in the manual(4) switching mode with a single operation, viz. by enabling(2) the manual mode switch defined by the following object: eSwitchAddrFdbManualMode.