The value of tmnxSubPppLacConnectionId indicates the connection
ID of the LAC L2TP session associated with this session.
The values of tmnxSubPppLacVrtrId and
tmnxSubPppLacConnectionId are the index in the table
TIMETRA-L2TP-MIB::tmnxL2tpSeStatusTable of the L2TP session
associated with this session.
The value of this object is only applicable if
tmnxSubPppTerminationType is 'lac', otherwise it is equal to zero.