This object indicates the reason for the operational state
change (cmedGatewayOperStatus) in the media gateway link.
mgcDirected (1) - The state change is directed from MGC.
mgDirected (2) - The state change is directed from MG.
mgcNotReachable (3) - The transport address of MGC is not
reachable.
numRetriesExpired (4) - The number of retires for connecting
MGC has exhausted (cmedxGatewayNumConnRetries).