The FEF represents Far End Fault. It is a protocol compliant with IEEE 802.3u standard to sense remote data link errors in a network. With the FEF function on media converter, it is very easy for the network administrator to detect the faults on the fiber media converter links. When a fiber link error is detected, the media converter on this side will transmit the far end fault signal over a fiber connection to inform the other media converter at the far end that the fault has occurred. Then, both copper links connected to the fiber link will be automatically disconnected. By using the FEF media converter, the fault on the link can be detected and troubleshoot immediately, preventing data from being transmitted to a failed link by cutting down the failed link and sending a far end fault to the media converter.
Operation of FEF on Media Converter
1. If there is a fault occurs in the RX end of fiber connection, FEF Media Converter A will detect the fault.
2. Then Media Converter A sends a far end fault to Media Converter B to inform that a fault has occurred in the RX end, which will disable the transmission of the TX fiber of Media Converter A.
3. Fiber Media Converter A takes down its copper link. On the corresponding Ethernet switch, the LED indicator shows a link disconnected status.
4. On the other side, Media Converter B takes down its copper link, too. The connected switch LED indicator shows a link downstate.