Failures Occurring When The Spanning Tree Functionality Is Used - Alaxala AX6700S series Troubleshooting Manual

in the configuration are correct, and that bandwidth monitoring, drop control, or the shaper is used
appropriately in the system configuration. For details about the procedure, see 3.25.1 Checking
the filters and QoS configuration information.

3.6.2 Failures occurring when the Spanning Tree functionality is used

If Layer 2 communication fails or the operating status of the Spanning Tree Protocol does not
conform to the network configuration when the Spanning Tree functionality is used, use the
analysis method described below to isolate the cause of the problem. For Multiple Spanning Tree,
perform the check for each CIST or each MST instance. When checking a root bridge, for example,
replace the word root bridge with CIST root bridge or root bridge for each MST instance.
Table 3-15: Failure analysis method for Spanning Tree Protocols
No. Items to check and commands
1 Execute the
show spanning-tree
command for the Spanning Tree
Protocol that caused the failure, and
then check the status of the protocol of
the Spanning Tree Protocol.
2 Execute the
show spanning-tree
command for the Spanning Tree
Protocol that caused the failure, and
then check the bridge identifier of the
root bridge for the Spanning Tree
Protocol.
3 Execute the
show spanning-tree
command for the Spanning Tree
Protocol that caused the failure, and
then check the port status and port role
for the Spanning Tree Protocol.
4 Execute the
show spanning-tree
command for the
statistics
Spanning Tree Protocol that caused the
failure, and then check whether BPDUs
were sent and received on the failed
port.
3. Troubleshooting Functional Failures During Operation
If the displayed status is
Enable
If Ring Protocol and PVST+ are used together, but the tree information
of the target VLAN is not displayed, go to No. 7.
If the displayed status is
Disable
stopped. Check the configuration.
If Ring Protocol and Multiple Spanning Tree are used together, go to No.
8.
Check whether the number of the PVST+ instances is within the capacity
limit.
If the bridge identifier of the root bridge indicates the root bridge defined
in the network configuration, go to No. 3.
If the bridge identifier of the root bridge does not indicate the root bridge
defined in the network configuration, check the network configuration
and other configurations.
If the port status and port role for the Spanning Tree Protocol are the
same as those defined in the network configuration, go to No. 4.
For versions prior to Version 10.6:
If the status of a port for which the loop guard functionality is enabled is
or , check whether the port is a designated port.
Blocking Discarding
If it is a designated port, delete the setting of the loop guard functionality.
If the port status and port role for the Spanning Tree Protocol are
different from the network configuration, check the status of neighboring
devices and their configurations.
Check the BPDU sending or receiving counter.
For a root port:
If the BPDU receiving counter has been incremented, go to No. 5.
If the counter has not been incremented, BPDUs might have been
discarded either by filtering or by bandwidth monitoring, drop
control, or the QoS control shaper. See 3.25.1 Checking the filters
and QoS configuration information and check for a problem. If you
do not find any problems, check the neighboring devices.
For a designated port:
If the BPDU sending counter has been incremented, go to No. 5.
If the counter has not been incremented, see 3.5 Network interface
communication failures.
Action
, go to No. 2.
, the Spanning Tree Protocol has
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