Troubleshooting guide

3. Troubleshooting Functional Failures During Operation
145
3.19 Communication failures in the IEEE 802.3ah/UDLD functionality
3.19.1 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 3-76: Failure analysis method when the IEEE 802.3ah/UDLD functionality is used
Note: IEEE 802.3ah/OAM: An OAM protocol defined in IEEE 802.3ah
IEEE 802.3ah/UDLD: Unidirectional link failure detection functionality specific for a Switch
that uses IEEE 802.3ah/OAM
No. Items to check and commands Action
1 Execute the
show efmoam command and
check the failure type for the port that was
deactivated by the IEEE 802.3ah/UDLD
functionality.
If
Down(loop) is displayed for Link status, an L2 loop might
have occurred in this network configuration. Revise the network
configuration.
If
Down(uni-link) is displayed for Link status, go to 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
command and make sure that a prohibited
configuration is not used.
If the count of
Unstable displayed for Info TLV has been
incremented, a configuration prohibited for the IEEE 802.3ah/
UDLD functionality might be used. Make sure only one device is
specified as the destination for the target physical port.
If the count of
Unstable for Info TLV 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 (however, using a relay device is not
recommended).
If the switches are directly connected, go to No. 5.
5 Execute the
show efmoam 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 filters and QoS control
configurations.
The control frames (
slow-protocol) used for the IEEE 802.3ah/
UDLD functionality might have been discarded by filters or QoS
control. See3.25.1 Checking the filters and QoS configuration
information and check for a problem. If there is no problem, go to
No. 7.
7 Test the line. See 6. Line Testing to perform a line test. If there is no problem, go
to No. 8.
8 Check the cable connection. The cable might be defective. Replace the cable used for the target
port.