Quick Reference Guide

Spanning Tree | 157
1. Configure switch R7. Enable STP globally and on associated ports; create MST instances and
associated VLANs:
2. Configure switch R4, exactly as above. The fact that this example shows the same port numbers
participating in the same two VLANs on each participating switch — R4, R5, and R7 — is simply an
expedient way to clone the configuration steps.
3. Configure switch R5, exactly as above.
4. Use the
show spanning-tree command to verify the STP convergence (see Figure 10-119 on page 159)
and
show spanning-tree mst port summary command (see Figure 10-125 on page 162) for behavior of
ports participating in the spanning tree.
Display Spanning Tree Configuration
Use the following commands to display MSTP configuration.
Note: Another configuration example is in Example of configuring STP on page 152.
Command Syntax Command Mode Purpose
show spanning-tree summary Privileged Exec Display STP settings and parameters for the switch.
See Figure 10-116 on page 158.
show spanning-tree [brief] Privileged Exec Display settings and parameters for the CIST. See
Figure 10-118 on page 159.
show spanning-tree mst summary Privileged Exec Display settings and parameters for all MST
instances.
R4 (Config)#interface vlan 2
R4 (Conf-if-vl-2)#tagged 1/0/2
R4 (Conf-if-vl-2)#tagged 1/0/3
R4 (Conf-if-vl-2)#exit
R4 (Config)#interface vlan 3
R4 (Conf-if-vl-3)tagged 1/0/2
R4 (Conf-if-vl-3)tagged 1/0/3
R4 (Config)#spanning-tree
R4 (Config)#spanning-tree configuration name span1
R4 (Config)#spanning-tree configuration revision 1
R4 (Config)#spanning-tree msti instance 2
R4 (Config)#spanning-tree msti vlan 2 2
R4 (Config)#spanning-tree msti instance 3
R4 (Config)#spanning-tree msti vlan 3 3
R4 (Config)#interface 1/0/2
R4 (Interface 1/0/2)#no shutdown
R4 (Interface 1/0/2)#spanning-tree port mode enable
R4 (Interface 1/0/2)#exit
R4 (Config)#interface 1/0/3
R4 (Interface 1/0/3)#no shutdown
R4 (Interface 1/0/3)#spanning-tree port mode enable
R4 (Interface 1/0/3)#exit
MST instance ID followed by VLAN ID