Indicates which ports are actually being monitored. All the monitored ports have to be non-trunking port and belong to the same Virtual LAN. The octet string contains one bit per port. Each bit within the octet string represents one port of the device. The ordering of ports represented within the octet string is in the same order as in the RFC 1493 dot1dStpPortTable.
The bit value interpretation is as follows:
1 = being monitored
0 = not being monitored