Enabling an entire MST region at once or exchanging one region configuration for another

This operation exchanges the currently active MSTP configuration with the currently pending MSTP configuration, making it possible to implement a new MSTP configuration with minimal network disruption or to exchange MSTP configurations for testing or troubleshooting purposes.

When configuring or reconfiguring MSTP, the switch recalculates the corresponding network paths. This can have a ripple effect throughout your network as adjacent MSTP switches recalculate network paths to support the configuration changes invoked in a single switch. Although MSTP employs rapid spanning tree operation, the convergence time for implementing MSTP changes can be disruptive to your network. However, by using the spanning-tree pending feature, you can set up an MSTP on the switch and then invoke all instances of the new configuration at the same time, instead of one at a time.

Syntax:

no spanning-tree pending [apply | config-name | config-revision | instance | reset]

Exchanges the currently active MSTP configuration with the current pending MSTP configuration. Options are as follows:

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

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.