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WCM1100 / WCM3100 / WCM-Serial / LHM1000 / LVM2000 User Manual
76-02-082 Rev N
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5.9.1.4 LAN / SFP Loops
The LAN and SFP ports support the following loopback options:
5.9.1.4.1 Phy Line Loop (OL)
In order to use the copper phy line loopback (loop receive back to transmit) first the PHY
LOOPs must be enabled. Once enabled, the OL loop may be selected for the PHY port.
Once selected, the loop will be applied for the configured timeout period to prevent a
permanent lock out problem occurring.
5.9.1.4.2 LAN External Loop (XLL)
In order to use the copper External line loopback (use an external loopback plug to loop
transmit back to receive) first the PHY LOOPs must be globally enabled. Once the EXT
loop is selected an external loopback plug may be connected and the port will become
active.
5.9.1.4.3 LAN/SFP OAM-RL loop
The LAN and SFP ports can request their OAM peer device apply a loopback. This loop is
only available where OAM is enabled on the link. According to the OAM loop standard,
loop prevention is enabled as the return path is blocked internally so traffic injected into a
port will only be counted internally. Check the port counters to verify the link.
In order to get test traffic around the loop, the Test Generator may be used to send and
receive test packets.
5.9.1.5 VCG Loops
The VCG ports support the following loopback options:
5.9.1.5.1 VCG OAM-RL loop
The VCG ports can request their OAM peer device apply a loopback. This loop is only
available where OAM is enabled on the link. According to the OAM loop standard, loop
prevention is enabled as the return path is blocked internally so traffic injected into a port
will only be counted internally. Check the port counters to verify the link.
