Description: This object specifies the identity of the physical port whose state is to be monitored. Each port index is a 16-bit integer in big endian order. 8-bit is the slot number, the other 8-bit is the port number. Default value is 0 length octet string. If this object is configured then the Preference Level of this interface will be adjusted dynamically depending on the state of the Track Port. The interface's Preference Level is reduced by value of Preference Level parameter when the Track Port states first changes from UP to DOWN. When the Track Port next comes up the interface's Preference Level is increased by the amount specified by the Preference Level. The router FSRP physical track port membership.