Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) - Manual (Page 354)

324 Multi-Service IronWare Switching Configuration Guide
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IEEE 802.1D Spanning Tree Protocol (STP)
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For example, the original timeout period on a device was configured for 60 seconds. The port
encounters a superior BPDU and the timer starts. Issuing a show span root-protect CLI command
displays the following information.
Brocade(config)#show span root-protect
Port VLAN Current State
1/4 1 Inconsistent state (56 seconds left on timer)
While the timer is in use, the timeout period is changed to 30 seconds through the issue of the
following command.
Brocade(config)# spanning-tree root-protect timeout 30
The timer continues the countdown and minus the time that have already elapsed (about 10
seconds) since the superior BPDU was detected. Issuing a show span root-protect CLI command
displays the following information.
Brocade(config)# show span root-protect
Port VLAN Current State
1/4 1 Inconsistent state (20 seconds left on timer)
Next, the timeout period is increased to 120 seconds.
Brocade(config)# spanning-tree root-protect timeout 120
Since the timer has not expired, it continues the countdown. The remaining time left is adjusted by
the time that has already elapsed (about 18 seconds) since the superior BPDU was detected.
Issuing a show span root-protect CLI command displays the following information.
Brocade(config)# show span root-protect
Port VLAN Current State
1/4 1 Inconsistent state (102 seconds left on timer)
Checking for Syslog messages
A Syslog message such as the following is generated after the Root Guard blocks a port.
Sep 9 18::39:27:I:STP: Root Guard Port 12/21, VLAN 10 inconsistent (Received
superior BPDU)
A Syslog message such as the following is generated after the Root Guard unblocks a port.
Sep 9 18::39:27:I:STP: Root Guard Port 12/21, VLAN 10 consistent (Timeout)
Checking for traps
The following SNMP traps are generated for Root Guard:
• snTrapStpRootGuardDetect is generated after the Root Guard blocks a port.
• snTrapStpRootGuardExpire is generated after a blocked port (due to Root Guard) goes back to
a Forwarding state
Refer to the Unified IP MIB Reference for details.