Bits set here represent defects and modes for switching the SONET path from the active CEM VC to another within this VC's group. Defects include: CEM errors (jitter buffer errors, missing packets, bad CEM headers). Separating these CEM defects into individually selectable bits, or adding other types of defect indications (e.g. OAM status) is for future study. Modes: The 'cemErrorStbyOK' mode setting is useful in APS network configurations where CEM traffic is not present on standby inbound VCs. Therefore they are expected to have CEM errors, but are still to be considered as viable switch- over candidates. cemErrorStbyOK essentially masks CEM errors when this CEM VC is in standby. 'revertive' mode is useful for non-preferred CEM VCs where you may want to switch back to a preferred VC that has no defects while the currently active VC also has no defects (see mplsCemVcApsRevertTimer). 'revertive' should NOT be used when standby VCs have no defect indications available. If 'revertive' is not set, then manual reversion is possible by simply setting the active CEM VC's admin status 'down', then 'up'. Preferred should NOT have 'revertive' set. 'hunt' mode is useful when standby VCs offer no defect indications (see mplsCemVcApsHoldOffTimer). 'hunt' should not be used when standby VCs have available defect indications. Hunting assumes standby VCs are good, if not the down timers will determine it's bad, and hunting continues. 'hunt' and 'revertive' are mutually exclusive.