Connectivity Fault Management (CFM), discussed in the IEEE 802.1Q-2011 standard and originally specified in the IEEE 802.1ag-2007 standard, allows you to detect, verify, and isolate connectivity failures in virtual bridged LANs.

Part of this specification is a toolset to manually check connectivity, which is sometimes referred to as Layer 2 ping.


The ExtremeXOS implementation of CFM is based on the IEEE 802.1Q-2011 standard.

There is no direct interaction between CFM and other Layer 2 protocols; however, blocked Spanning Tree Protocol (STP) ports are taken into consideration when forwarding CFM messages.