Troubleshooting guide

3. Troubleshooting Functional Failures During Operation
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3.6.3 Failures occurring when the Ring Protocol functionality is used
This subsection describes failures occurring in the Autonomous Extensible Ring Protocol.
The Autonomous Extensible Ring Protocol (abbreviated hereafter to Ring Protocol) is a Layer 2
network redundancy protocol for ring topologies.
If communication is not possible when the Ring Protocol is used, use the following analysis
flowchart to determine the problem and isolate the cause.
Figure 3-3: Analysis flowchart
If operation cannot be performed correctly or a ring network failure is detected when the Ring
Protocol is used, use the failure analysis method described in the table below to isolate the cause
of the problem for all nodes in the target ring network.
5 Execute the show spanning-tree
command with the
detail parameter
for the Spanning Tree Protocol that
caused the failure, and then check the
bridge identifier for the received
BPDUs.
Make sure the root bridge identifier and sending bridge identifier for the
received BPDUs are the same as those defined in the network
configuration. If they are different from the network configuration, check
the status of the neighboring devices.
6 Check whether the value for maximum
number of Spanning Tree Protocols, one
of which caused the failure, is within the
capacity limit.
Set a value within the capacity limit.
For details about capacity limits, see the Configuration Guide.
7 Make sure that only one VLAN
intended to be used in PVST+ mode is
set in
vlan-mapping for Ring
Protocol.
Set the target VLAN in
vlan-mapping for Ring Protocol if not set. If
multiple VLANs are set in
vlan-mapping, specify only one VLAN in
the vlan-mapping setting.
8 Make sure that VLANs intended to be
used in an MST instance are correctly
set in vlan-mapping for Ring
Protocol.
If any of the target VLANs are not set in
vlan-mapping for Ring
Protocol, set them to be consistent with the VLANs for Multiple
Spanning Tree.
No. Items to check and commands Action