Spanning-Tree - Cisco ME 3400 Command Reference Manual

spanning-tree

spanning-tree
Use the spanning-tree interface configuration command with no keywords on an enhanced network
interface (ENI) to enable a spanning-tree instance on the interface. Use the no form of this command to
return to the default setting of disabled.
Syntax Description
This command has no arguments or keywords.
Defaults
The Spanning-Tree Protocol (STP) is disabled on ENIs.
Command Modes Interface configuration
Command History Release
12.2(44)SE
Usage Guidelines
This command is supported only on ENIs and on EtherChannel port channels that contain ENIs.
STP is not supported on user network interfaces (UNIs) and it is disabled by default on ENIs. Use this
command to enable SPT on an ENI. To set a port as an ENI, enter the port-type eni interface
configuration command. Once STP is enabled on an ENI, all other STP interface configuration
commands are available on the interface.
The switch supports only one spanning-tree instance on a VLAN. When NNIs and ENIs with spanning
tree enabled are in the same VLAN, they belong to the same spanning-tree instance.
STP is enabled by default on NNIs. UNIs are typically customer-facing ports and do not participate in
the spanning tree of the service provider. However, if you configure a customer-facing port as an ENI
and enable spanning tree, the ENI could become the spanning tree root port unless you configure root
guard on the port by using the spanning-tree guard root interface configuration command. A
customer-facing ENI with STP enabled participates in the same spanning tree as the service-provider
facing NNI.
Note Exercise caution when enabling STP on a customer-facing ENI.
Examples This example shows how to enable STP on a port:
Switch(config)# interface fastethernet0/1
Switch(config-if)# port-type eni
Switch(config-if)# spanning-tree
You can verify your setting by entering the show spanning-tree interface privileged EXEC command.
Cisco ME 3400 Ethernet Access Switch Command Reference
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spanning-tree
no spanning-tree
Modification
This command (without keywords) was introduced.
Chapter 2 Cisco ME 3400 Ethernet Access Switch Cisco IOS Commands
OL-9640-07