KB.15.15

4 Rapid per-VLAN spanning tree (RPVST+) operation

NOTE: All commands previously in the Summary of commands table are indexed under the entry

Command syntax.

Overview

RPVST+ is a proprietary spanning tree implementation that extends RSTP (802.1w) to run a separate

spanning tree for each VLAN on the switch, and ensures that only one active, loop-free path exists

between any two nodes on a given VLAN.

Configuring RPVST+ at a glance

The general steps for configuring RPVST+ via the CLI are:

1. Select RPVST+ as the active spanning tree mode by entering the following command:

spanning-tree mode rapid-pvst

To begin with the default RPVST+ configuration (recommended), go to step 6.

2. Configure global spanning tree parameters.

3. Configure per-VLAN parameters.

4. Configure per-port per-VLAN parameters. These commands affect RPVST+ operation on traffic

associated with the specified VLAN(s) through the specified port(s).

5. Configure per-port parameters. These commands affect RPVST+ operation for all traffic through

the specified port(s).

6. Use one of the following commands to enable RPVST+ spanning tree operation on the switch:

• One or more selected VLANs: spanning-tree vlan vid-list

• The first 400 VLANs: spanning-tree

Any VLANs in excess of the first 400 would have RPVST+ disabled. In this case, use the

[no] spanning-tree vlan vid-list command to change the mix of RPVST+

enabled and disabled VLANs.

Additional configuration options include:

• “Configuring BPDU filtering” (page 136)

• “Allowing traffic on VLAN ID (PVID) mismatched links” (page 139)

• “Configuring STP loop guard” (page 140)

Configuring RPVST+

Selecting RPVST+ as the spanning tree mode

Syntax:

[no] spanning-tree mode [ mstp | rapid-pvst ]

Specifies that spanning tree will run in MSTP (default) or RPVST+ mode.

To view Mode, use the show run command. This will eliminate confusion if there

is an RPVST configuration but MSTP is running. This will lead to a change in the

existing factory default setting.

Overview 131