NEC IP8800/S6700 manual Failures on Using Ring Protocol, Spanning Tree Failure Analysis Method

3. Troubleshooting Functional Failures in Operation

bridge for each MST instance for route bridge, when checking the route bridge.

Table 3-14: Spanning Tree Failure Analysis Method

No.	Troubleshooting Steps and Command	Action
1	Execute the show spanning-tree	If shown as Enable, go to No. 2.
	command for the failed spanning tree and	When tree information is not displayed while Ring Protocol and PVST+ both are
	check the protocol status of the spanning tree.
		in use, go to No.7.
		If shown as Disable, the spanning tree is suspended. Check the configuration.
		Ring Protocol and multiple spanning tree both are used, go to No.8.
		Check to see if the number of PVST+s is within the conditions of accommodation.
2	Execute the show spanning-tree	Go to No. 3 if the bridge identifier of the route bridge complies with the network
	command for the failed spanning tree and	configuration.
	check the bridge identifier of the route bridge
		Check the network configuration and configuration if the bridge identifier of the
	for the spanning tree.
		route bridge does not comply with the network configuration.
3	Execute the show spanning-tree	Go to No. 4 if the spanning tree port status and port role comply with the network
	command for the failed spanning tree and	configuration.
	check the port status and the port role of the
		When the systems before Ver10.6 is used:
	spanning tree.
		If the port status of the port for which the loop guard function is defined is
		Blocking or Discarding, check to see if the port is a designated port. If the port is
		a designated port, delete the setting of the loop guard function.
		If the spanning tree port status and port role do not comply with the network
		configuration, check the neighboring system status and configuration.
4	Execute the show spanning-tree	Check the BPDU sending/receiving counter.
	statistics command for the failed	[Root port]
	spanning tree and check BPDU sending and	Go to No. 5 if the BPDU receiving counter has been incremented.
	receiving on the failed port.	If not so, BPDU may have been discarded by filtering, or BPDU may have
		been discarded through bandwidth monitoring, discarding control, or shaper
		of the QoS control. See "3.23.1 Checking Filtering/QoS Setting Information"
		to check for it. If no problem is found, check the neighboring system.
		[Designated port]
		Go to No. 5 if the BPDU sending counter has been incremented. Otherwise,
		see "3.4 Network Interface Communication Failure."
5	Execute the show spanning-tree	Confirm that the received BPDU route bridge identifier and sending bridge
	command for the failed spanning tree with	identifier comply with the network configuration. Otherwise, check the
	"detail" parameter specified, and check the	neighboring system status.
	received BPDU bridge identifier.
6	Check to see if the maximum number of	Set up the number within the range of the accommodating conditions. For the
	failed spanning trees is within the	accommodating conditions, see "Configuration Settings."
	accommodating conditions.
7	Check to see if vlan-mapping is applied to	If vlan-mapping of Ring Protocol is not applied to the target VLAN, configure it.
	the single VLAN that is to operate with	In addition, if multiple VLANs are applied to the vlan-mapping, review the
	PVST+.	vlan-mapping and change it to a single VLAN.
8	Check to see if the vlan-mapping of VLANs	If vlan-mapping of Ring Protocol is not applied to the target VLAN, adjust it to
	to be operated with MST instances is the	match the configuration of VLANs with multiple spanning tree enabled.
	same as that of Ring Protocol.

3.5.3Failures on Using Ring Protocol

This subsection describes Autonomous Extensible Ring Protocol failure.

The Autonomous Extensible Ring Protocol is redundant protocol on the layer 2 network for ring topology, refer to it as "Ring Protocol" hereafter.

When the communication is disabled during Ring Protocol operation, follow the analysis flow to identify the symptom

41