Description: A string of octets containing one bit per VLAN for VLANS with VlanIndex values of 0 through 2047. The first octet corresponds to VLANs with VlanIndex values of 0 through 7; the second octet to VLANs 8 through 15; etc. The most significant bit of each octet corresponds to the lowest value VlanIndex in that octet.

For each VLAN, if it is mapped to this MST instance, then the bit corresponding to that VLAN is set to '1'. Each VLAN can only be mapped to one unique MST instance with the range from 0 to stpxSMSTMaxInstanceNumber. If the bit corresponding to a VLAN is changed from '1' to '0', then that VLAN will be automatically mapped to SMST instance 0 by the device. If the bit corresponding to a VLAN is changed from '0' to '1', then that VLAN will be automatically removed from the MST instance this VLAN was previously mapped to. If the length of this string is less than 256 octets, any 'missing' octets are assumed to contain the value of zero.