PLANET GST-702 - Manual (Page 12)

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4. 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 con-
verter 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.
4.1 Link Loss Carry Forward (LLCF)
The GST-70X modules 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 GST-70X for remote connectivity.
Management Switch/Hub Media Media Switch/Hub Management
Station w/SNMP Converter Converter w/SNMP Station
● LED lit = established link ○ LED unlit = no link
LLCF is ON LLCF is ON
TP Fiber
Cable
TP
If the connection breaks, GST-70X that link loss forward to the switch/hub which generates a trap to the management
station. The administrator can then determine the source of the issue.
Management Switch/Hub Media Media Switch/Hub Management
Station w/SNMP Converter Converter w/SNMP Station
● LED lit = established link ○ LED unlit = no link
LLCF is ON
LLCF is ON
TP Broken
Fiber
TP
#
Notice:
1. When connecting GST-70X with LLCF default enabled to an auto-negotiating-capable device, force both sides of the
configuration to 10 or 100Mbps full or half duplex. This allows the converter to immediately see link pulses and start
passing data.
2. Units are shipped with the default LLCF function enabled.