Link Loss Return (Llr) - Planet IGTP-802T User Manual

If the connection breaks, the IGTP-80xT whose link is lost forwards 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
Station w/SNMP
 LED lit = established link
The converter is shipped with the default LFP (LLCF/
LLR) function disabled. This feature can also be turned
on on-purpose. If you are familiar with the network
installation and for diagnostic purpose (i.e. check which
end is broken), you can turn it on and the converter will
Note
take effect immediately. Otherwise, please put it in the
default position.

3.2 Link Loss Return (LLR)

The fiber ports of the IGTP-80xT have been designed with an LLR
function for troubleshooting a remote connection. LLR works in
conjunction with LLCF.
When LLR is enabled*, the port's transmitter will shut down when
its receiver fails to detect a valid receive link. LLR should only be
enabled on one end of the link and is typically enabled on either the
unmanaged or remote device.
The diagram below shows a typical network configuration with a good
link status using the IGTP-80xT for remote connectivity. Note that LLR
is enabled as indicated in the diagram.
Media
Converter
LFP ON
Broken
TP
Fiber
Cable
 LED unlit = no link
Media Switch/Hub
Converter w/SNMP
LFP ON
TP
Management
Station
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