Troubleshooting guide

3. Troubleshooting Functional Failures During Operation
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3.12 Communication failures in the IEEE 802.3ah/UDLD functionality
3.12.1 Port is in inactivate status by the IEEE 802.3ah/UDLD functionality
If the IEEE 802.3ah/UDLD functionality has deactivated a port, isolate the cause of the
problem according to the failure analysis method described in the following table.
Table 3-35 Failure analysis method when the IEEE 802.3ah/UDLD functionality is used
No. Items to check and commands Action
1 Execute the show efmoam
operation command and check the
failure type for the port that was
deactivated by the IEEE
802.3ah/UDLD functionality.
If Down is displayed for Link status, continue with No. 2.
2 Make sure the IEEE 802.3ah/OAM
functionality is enabled on the
partner switch.
 If the IEEE 802.3ah/OAM functionality is not enabled on the
partner switch, enable the functionality.
 If the IEEE 802.3ah/OAM functionality is enabled on the
partner switch, go to No. 3.
3 Execute the show efmoam
statistics operation command
and check the information displayed
for Thrashings.
 If the value of Thrashings has been incremented, a
prohibited configuration (multiple connection destinations) is
being used. Make sure only one device is specified as the
destination for the target physical port.
 If the Thrashings value has not been incremented, go to
No. 4.
4 Make sure the Switch is directly
connected to the partner switch.
 If a media converter or hub is connected between switches,
review and correct the network configuration so that the
Switch is directly connected to the partner switch. If a relay
device is absolutely necessary, use a media converter that
allows the link status on both sides to be identical (this action
is not recommended, however).
 If the switches are directly connected, go to No. 5.
5 Execute the show efmoam
operation command and check the
number of times a response timeout
occurred during failure detection.
 If the value displayed for udld-detection-count is less
than the initial value, an unidirectional link failure is more
likely to be detected even if a failure has not actually
occurred. Change this value.
 If the value displayed for udld-detection-count is equal
to or more than the initial value, go to No. 6.
6 Check the filtering and QoS control
configurations.
 The control frames (slow-protocol) used for the IEEE
802.3ah/UDLD functionality might have been discarded by
filtering or QoS control. For details about the procedure,
see
3.13.1 Checking the filtering and QoS control
configuration information.
 If there is no problem, go to No. 7.
7 Check the cable connection. The cable might be defective. Replace the cable used for the
target port.
Note: IEEE 802.3ah/OAM: An OAM protocol defined in IEEE 802.3ah
IEEE 802.3ah/UDLD: Unidirectional link failure detection functionality that uses IEEE
802.3ah/OAM