A string of octets containing one bit per VLAN for
VLANS with VlanIndex values 1024 through 2047. The
first octet corresponds to VLANs with VlanIndex values
1024 through 1031; the second octet to VLANs 1032
through 1039 etc. The most significant bit of each
octet corresponds to the lowest VlanIndex value in that
octet.
For each VLAN that is mapped to this MSTP instance,
the bit corresponding to that VLAN is set to '1'.
This object is only instantiated on devices with
support for VlanIndex values up to 4095.