The value of tmnxMcRingVlanMapExcl specifies the set of VLAN ID's
associated with the SAP's that are to be excluded from control by the
multi-chassis ring. It is a bitmap that associates bit i
with VLAN ID i, with i in [0..4094]. 4095 corresponds to a dot1q default
or capture SAP.
In case of QinQ encapsulation, the outermost VLAN ID is referred to.
Setting the value of tmnxMcRingVlanMapExcl to the empty string is
equivalent to setting it to 512 zeroes.