A string of octets containing one bit per VLAN for
VLANs 0 to 2047 that are active in this FabricPath
topology entry.
If the bit corresponding to a VLAN is set to '1', then
the VLAN is active in this FabricPath topology. If
the bit is set to '0', then the VLAN is not configured
in this FabricPath topology.