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Chapter 34: Spanning Tree Commands
spanning-tree
spanning-disabled
spanning-tree
tc-prop-stop
When Root Guard is enabled, and the switch receives a superior BPDU
•
on this port, it is set to the Discarding state until it stops receiving
superior BPDUs for a fixed recovery period. While in the discarding
state, no traffic is forwarded across the port.
Root Guard can be used to ensure that the root bridge is not formed at
•
a suboptimal location. Root Guard should be enabled on any designated
port connected to low-speed bridges which could potentially overload a
slower link by taking over as the root port and forming a new spanning
tree topology. It could also be used to form a border around part of the
network where the root bridge is allowed.
•
When spanning tree is initialized globally on the switch or on an
interface, the switch will wait for 20 seconds to ensure that the
spanning tree has converged before enabling Root Guard.
E
XAMPLE
Console(config)#interface ethernet 1/5
Console(config-if)#spanning-tree edge-port
Console(config-if)#spanning-tree root-guard
Console(config-if)#
This command disables the spanning tree algorithm for the specified
interface. Use the no form to re-enable the spanning tree algorithm for the
specified interface.
S
YNTAX
[no] spanning-tree spanning-disabled
D
S
EFAULT
ETTING
Enabled
C
M
OMMAND
ODE
Interface Configuration (Ethernet, Port Channel)
E
XAMPLE
This example disables the spanning tree algorithm for port 5.
Console(config)#interface ethernet 1/5
Console(config-if)#spanning-tree spanning-disabled
Console(config-if)#
This command stops the propagation of topology change notifications
(TCN). Use the no form to allow propagation of TCN messages.
S
YNTAX
[no] spanning-tree tc-prop-stop
– 1043 –
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