Cisco Nexus 5000 Series Switch CLI Software Configuration Guide, NX-OS 4.0(1a)N1 (OL-16597-01, January 2009)

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Cisco Nexus 5000 Series Switch CLI Software Configuration Guide
OL-16597-01
Chapter 9 Configuring MST
Configuring MST
Mapping Secondary VLANs to Same MSTI as Primary VLANs for Private VLANs
When you are working with private VLANs on the system, all secondary VLANs must be in the same
MSTI and their associated primary VLAN.
To accomplish this synchronization automatically, perform this task:
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.
Note 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.
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.
Note 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.
Command Purpose
Step 1
switch# configure terminal
Enters configuration mode.
Step 2
switch(config)# spanning-tree mst
configuration
Enters MST configuration submode.
Step 3
switch(config-mst)# private-vlan
synchronize
Automatically maps all secondary VLANs to the
same MSTI and their associated primary VLAN for
all private VLANs.