Spanning-Tree Operation

802.1s Multiple Spanning Tree Protocol (MSTP)

1.Configure the VLANs you want included in any instances in the new region. When you create the pending region, all VLANs configured on the switch will be assigned to the pending IST instance unless assigned to other, pending MST instances.

2.Configure MSTP as the spanning-tree protocol, then execute write mem and reboot. (The pending option is available only with MSTP enabled.)

3.Configure the pending region name to assign to the switch.

4.Configure the pending config-revisionnumber for the region name.

5.If you want an MST instance other than the IST instance, configure the instance number and assign the appropriate VLANs (VIDs). (The pending command creates the region’s IST instance automatically.)

6.Repeat step 5 for each additional MST instance you want to configure.

7.Use the show spanning-tree pending command to review your pending configuration (page 80).

8.Use the spanning-tree pending apply command to exchange the currently active MSTP configuration with the pending MSTP configuration.

Syntax: spanning-tree pending < apply config-name config-revision instance reset >

apply

Exchanges the currently active MSTP configuration with the pending MSTP configuration.

config-name

Specifies the pending MST region name. Must be the same for all MSTP switches in the region. (Default: The switch’s MAC address.)

config-revision

Specifies the pending MST region configuration revision number. Must be the same for all MSTP switches in the region. (Default: 0).

instance < 1..16 > vlan [< vid vid-range>

Creates the pending instance and assigns one or more

VLANs to the instance.

reset

Copies the switch’s currently active MSTP configuration to the pending configuration. This is useful when you want to experiment with the current MSTP configuration while maintaining an unchanged version.

5-73