Each port in a pair is constantly monitored for signs of failure. Failure information is used to automatically change the active port from main to standby or vice-versa. Each port may be in one of three states. Failed(1) indicates there is a loss of signal on this port. A port in this state cannot be active. Secondly ok(2). This state indicates that the port is capable of carrying traffic but is at the moment acting in the role of backup link. The other port in this pair will be in the Ok-and-active(3) state. Ok-and-active(3) means what it says, this port is capable of carrying traffic and is so doing at the time this parameter has been read.