Loop Detection; Show Loopd - Siemens SCALANCE XM-400 Configuration Manual

Diagnostics

12.5 Loop detection

12.5 Loop detection
With the "Loop detection" function, you specify the ports for which loop detection will be
activated. The ports involved send special test frames - the loop detection frames. If these
frames are sent back to the device, there is a loop.
A "Local loop" involving this device means that the frames are received again at a different
port of the same device. If the sent frames are received again at the same port, there is a
"remote loop" involving other network components.
Note
A loop is an error in the network structure that needs to be eliminated. The loop detection
can help to find the errors more quickly but does not eliminate them.
Note
Note that loop detection is only possible at ports that were not configured as ring ports or
standby ports.
With the commands in this section, you start loop detection and decide which actions will be
used on the ports affected if loops are detected.
12.5.1

show loopd

Description
With this command, you display the information on loop detection.
Detected loops are shown.
Requirement
You are in the User EXEC mode or in the Privileged EXEC mode.
The command prompt is as follows:
cli>
Syntax
Call the command without parameters:
show loopd
For information on names of addresses and interfaces, refer to the section "Addresses and
interface names (Page 30)".
592
or
cli#
SCALANCE XM-400/XR-500 Command Line Interface
Configuration Manual, 05/2014, C79000-G8976-C252-07