1) Device B detects loss of signal. Local fault is signaled by PHY of Device B to Device B.
2) Device B ceases transmission of MAC frames and transmits remote fault to Device A.
3) Device A receives remote fault from Device B.
4) Device A stops sending frames, continuously generates Idle.
The Extreme Networks implementation of LFS conforms to the IEEE standard 802.3ae-2002.
For more information please refer to IEEE standard 802.3ae-2002
A local fault is usually caused by a lack of light being received.
No light coming from the other end of the connection can mean the other end is not plugged in or the physical fiber connection is misaligned or dirty.