The set of the device's member ports that belong
to the VLAN. It has the VLAN membership information
of up to 2k ports with the port number starting from
the information indicated in vmMembershipPortRangeIndex
object of the same row. For example, if the value
of vmMembershipPortRangeIndex is 'twoKto4K', the
port number indicated in this object starting from
2049 and ending to 4096.
A port number is the value of dot1dBasePort for
the port in the BRIDGE-MIB (RFC 1493).