Indicates the state of VC OAM.
downRetry(1) -- Loopback failed. Retry sending
loopbacks with retry frequency.
VC is up.
verified(2) -- Loopback is successful.
notVerified(3) -- Not verified by loopback,
AIS/RDI conditions are cleared.
upRetry(4) -- Retry successive loopbacks.
VC is down.
aisRDI(5) -- Received AIS/RDI. Loopback are
not sent in this state.
aisOut(6) -- Sending AIS. Loopback and reply are
not sent in this state.
notManaged(7) -- VC is not managed by OAM.