PLANET IGTP-80xT Series - Manual (Page 25)

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3. Link Pass Through Function
The LFP function includes the Link Fault Pass Through function (LLCF/
LLR) and the DIP Switch design. LLCF/LLR can immediately alarm
administrators the problem of the link media and provide efficient
solution to monitor the net. The DIP Switch provides disable or enable
the LFP function.
LLCF (Link Loss Carry Forward) means when a device connected to
the converter and the TP line loss the link, the converter’s fiber will
disconnect the link of transmit. LLR (Link Loss Return) means when
a device connected to the converter and the fiber line loss the link,
the converter’s fiber will disconnect the link of transmit. Both can
immediately alarm administrators the problem of the link media and
provide efficient solution to monitor the net.
3.1 Link Loss Carry Forward (LLCF)
The IGTP-80xT incorporates default LLCF function for troubleshooting a
remote connection; the Fiber/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 IGTP-80xT 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