Procedure
Purpose
Command or Action
Enters global configuration mode.
switch#
configure terminal
Step 1
Enters MST configuration submode.
switch(config)#
spanning-tree mst
configuration
Step 2
Automatically maps all secondary VLANs to the
same MSTI as their associated primary VLAN in
all private VLANs.
switch(config-mst)#
private-vlan
synchronize
Step 3
This example shows how to automatically map all the secondary VLANs to the same MSTI as their associated
primary VLANs in all private VLANs:
switch#
configure terminal
switch(config)#
spanning-tree mst configuration
switch(config-mst)#
private-vlan synchronize
Configuring the Root Bridge
You can configure the switch to become the root bridge.
The root bridge for each MSTI should be a backbone or distribution switch. Do not configure an access
switch as the spanning tree primary root bridge.
Note
Enter the
diameter
keyword, which is available only for MSTI 0 (or the IST), to specify the network diameter
(that is, the maximum number of hops between any two end stations in the network). When you specify the
network diameter, the switch automatically sets an optimal hello time, forward-delay time, and maximum-age
time for a network of that diameter, which can significantly reduce the convergence time. You can enter the
hello
keyword to override the automatically calculated hello time.
With the switch configured as the root bridge, do not manually configure the hello time, forward-delay
time, and maximum-age time using the
spanning-tree mst hello-time
,
spanning-tree mst forward-time
,
and
spanning-tree mst max-age
global configuration commands.
Note
Procedure
Purpose
Command or Action
Enters global configuration mode.
switch#
configure terminal
Step 1
Configures a switch as the root bridge as follows:
switch(config)#
spanning-tree
mst instance-id root
{
primary
|
Step 2
Cisco Nexus 6000 Series NX-OS Layer 2 Switching Configuration Guide, Release 7.x
83
Configuring Multiple Spanning Tree
Configuring the Root Bridge
