The value of tmnxDot1agCfmMepMgmtPrimaryVid specifies, along with
tmnxDot1agCfmMepMgmtIfIndex, the Primary VID of the MEP.
This object refers directly to
IEEE8021-CFM-MIB::dot1agCfmMepPrimaryVid.
This object must be specified during row creation when
tmnxDot1agCfmMepMgmtIfIndex is specified.