CANOGA PERKINS N525 Ethernet Termination Service Unit - Manual (Page 18)

2-8 Ethernet Termination Service Unit
Remote Fault
If an optical port loses the receive optical signal, it sends a Remote Fault (RMTF)
signal on its Transmit to the distant end on the optical link. The Rx LED is off, and
an alarm flags the link loss on the optical port. When a optical port receives a
Remote Fault signal, the Rx LED lights red and an alarm flags the remote side
optical link failure. Both local and remote link partners must be configured to the
same RMTF enable/disable setting. RMTF complies with the IEEE802.3u Remote
Fault standard. See Figure 18.
Usr
Prt
Ext
Prt
Rx
Rx Tx
Tx
Usr
Prt
Ext
Prt
Rx
Rx Tx
Tx
RMTF
Local Device Remote Device
• Tx transmits RMTF to remote device
• Local device Rx turns OFF
• Local device Rx detects link loss
• Remote device Rx lights red
Figure 18 – Remote Fault Signal
Link Loss Forwarding
When Link Loss Forwarding (LLF) is enabled, a fault on one side of the N525
propagates to the other side to notify that device and stops signal transmission
(brings down the link). See Figure 19. Set the LLF propagation to User to
Extension, Extension to User, or both directions. Set this in the User Interface at the
Functional Configuration screen(reference
Managing the Network Interface ).
Figure 19 – Link Loss Forwarding Propagation