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4. Link Fault Pass Through (LFP)
The LFP function includes the Link Fault Pass Through
function (LLCF/LLR) and the DIP Switch design. LLCF/LLR can
immediately alarm administrators to a link media problem and
provide an efficient solution to monitor the net. The DIP Switch
allows you to disable or enable the LFP function.
LLCF (Link Loss Carry Forward) is when a device is connected
to the converter and the TP line loses the link, the converter’s
fiber will disconnect the link of transmit. LLR (Link Loss Return)
means when a device is connected to the converter and the
fiber line loses the link, the converter’s fiber will disconnect the
link of transmit. Both can immediately alarm administrators of a
link media problem and provide an efficient solution to monitor
the net.
Link Loss Carry Forward (LLCF)
The FCU-2805P-SFP incorporates an LLCF function for
troubleshooting a remote connection. When the LFP function is
enabled, the FL / TP ports do not transmit a link signal until
they receive a link signal from the opposite port.
The diagram below shows a typical network configuration with a
good link status using FCU-2805P-SFP for remote connectivity.
Media
Converter
Management
Station
Switch/Hub
w/SNMP
Management
Station
Media
Converter
Switch/Hub
w/SNMP
TP
TP
Fiber
Cable
LFP ON
LFP ON
l
LED lit = established link
°
LED unlit = no link
Media
Converter
Management
Station
Switch/Hub
w/SNMP
Management
Station
Media
Converter
Switch/Hub
w/SNMP
TP
TP
Broken
Fiber
Cable
LFP ON
LFP ON
l
LED lit = established link
°
LED unlit = no link
