This object is used in decoding 'mepUp' and 'mepDown' events.
** For 'mepUp', the following codes are relevant:
'new' - This is the very first time the device
receives a CC message from the remote MEP.
'returning' - The device received a CC message from a
remote MEP for which it had an expired
CCDB entry.
'portState' - The device received a CC message from a
remote MEP for which it has a valid CCDB
entry, and the message indicates a port
status change.
** For 'mepDown', the following codes are relevant:
'lastGasp' - The device received a CC message from a
remote MEP with zero lifetime.
'timeout' - The local CCDB entry for the remote MEP
expired.
'configClear' - A previous CC message from a MEP that
triggered a configuration error event
is cleared.
'loopClear' - A previous CC message from a MEP that
triggered a loop error event is cleared.
'xconnectClear' - A previous CC message from a MEP that
triggered a crossconnect error event
is cleared.
'unknownClear' - A previous CC message from a MEP that
triggered an unknown MEP event is
cleared.