This object indicates the current gateway overload
notification state.
The value of 'true' means the gateway will notify
MGC when the gateway is overloaded.
The value of 'false' means the gateway won't notify
MGC when the gateway is overloaded.
This object is 'true' when cmedxOverloadControlEnabled
is set to 'true' and at least one of MGCs enabled
gateway overload notification (cmedxOverloadNotifyEnabled
is not 0).