Description: The current status of the APS group.

modeMismatch

Modes other than 1+1 unidirectional monitor protection line K2 bit 5, which indicates the architecture and K2 bits 6-8, which indicate if the mode is unidirectional or bidirectional. A conflict between the current local mode and the received K2 mode information constitutes a mode mismatch.

channelMismatch

This bit indicates a mismatch between the transmitted K1 channel and the received K2 channel has been detected.

psbf

This bit indicates a Protection Switch Byte Failure (PSBF) is in effect. This condition occurs when either an inconsistent APS byte or an invalid code is detected. An inconsistent APS byte occurs when no three consecutive K1 bytes of the last 12 successive frames are identical, starting with the last frame containing a previously consistent byte. An invalid code occurs when the incoming K1 byte contains an unused code or a code irrelevant for the specific switching operation (e.g., Reverse Request while no switching request is outstanding) in three consecutive frames. An invalid code also occurs when the incoming K1 byte contains an invalid channel number in three consecutive frames.

feplf

Modes other than 1+1 unidirectional monitor the K1 byte for Far-End Protection-Line failures. A Far-End Protection-Line defect is declared based on receiving SF on the protection line.

extraTraffic

This bit indicates whether extra traffic is currently being accepted on the protection line.