Detecting Remote Faults

Fault detection is either based on flags or fault event type, length, and values (TLVs) received in OAM protocol data units (PDUs). Flags that trigger a link fault are:

• Critical Event
• Dying Gasp
• Link Fault

The link event TLVs are sent by the remote DTE by means of event notification PDUs. Link event TLVs are:

• Errored Symbol Period Event
• Errored Frame Event
• Errored Frame Period Event
• Errored Frame Seconds Summary Event