METRODATA LTD
WCM1100 / WCM3100 / WCM-Serial / LHM1000 / LVM2000 User Manual
76-02-082 Rev N
155 of 169
5.9.1.1 Physical Loops
As the WCM units are LAN service delivery platforms and loopbacks within an Ethernet
can cause major problems due to broadcast storms, great care must be taken when using
loopbacks for testing.
To make it more difficult to inadvertently apply a loopback the Physical Loopback control is
used to control the types of loop available for testing.
When Physical Loops are disabled, only Safe loops may be applied including OAM loops
and the WAN port Remote Loop. Both of these loop types disconnect the port selected for
test from the LAN and therefore broadcast loops will not occur. The WAN loops are used
with the BERT tester to test the WAN port.
When Physical Loops are enabled, true physical layer loops are applied and LAN packets
are looped. This mode should not be used when connected to a LAN network and is
intended for use with LAN test equipment.
5.9.1.2 Timeout
Since loopbacks may make a unit inaccessible, a timeout allows the loop to be
automatically removed after a predefined time. A value of zero disables this timeout.
5.9.1.3 ROL (Remote Outside Loop)
When a unit is configured to request a Remote Loop (RL) on any port it will send out a
pattern to request the remote unit apply a loop.
The ROL setting determines the action the WCM will take on receiving the RL Loop Up
command.
ENABLED
Apply ROL in response to Loop Up command
DISABLED
Ignore Loop Up Command
