IEEE 802.1ag
The standard addressed by the IEEE 802.1ag working group, called Connectivity Fault Management, specifies the protocols, procedures, and managed objects to support fault management in data transport. 802.1ag is used for fault monitoring in Provider Backbone Bridges ( PBB), among other applications. The standard enables the detection of connection paths across bridges and local area networks derived from source and destination addresses to and from specified network users. The method can detect and isolate connection errors.