20-18
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MSTP-enabled switches are in the same region only when they have the same format selector (a
802.1s-defined protocol selector, which is 0 by default and cannot be configured), MST region
name, VLAN-to-instance mapping table, and revision level.
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The 3Com switches 4500 support only the MST region name, VLAN-to-instance mapping table,
and revision level. Switches with the settings of these parameters being the same are assigned to
the same MST region.
Configuration example
# Configure an MST region named
info
, the MSTP revision level being level 1, VLAN 2 through VLAN
10 being mapped to MSTI 1, and VLAN 20 through VLAN 30 being mapped to MSTI 2.
<Sysname> system-view
[Sysname] stp region-configuration
[Sysname-mst-region] region-name info
[Sysname-mst-region] instance 1 vlan 2 to 10
[Sysname-mst-region] instance 2 vlan 20 to 30
[Sysname-mst-region] revision-level 1
[Sysname-mst-region] active region-configuration
# Verify the above configuration.
[Sysname-mst-region] check region-configuration
Admin configuration
Format selector :0
Region name :info
Revision level :1
Instance Vlans Mapped
0 1, 11 to 19, 31 to 4094
1 2 to 10
2 20 to 30
Specifying the Current Switch as a Root Bridge/Secondary Root Bridge
MSTP can automatically choose a switch as a root bridge through calculation. You can also manually
specify the current switch as a root bridge by using the corresponding commands.
Specify the current switch as the root bridge of a spanning tree
Follow these steps to specify the current switch as the root bridge of a spanning tree:
To do...
Use the command...
Remarks
Enter system view
system-view
—
Specify the current switch as
the root bridge of a spanning
tree
stp
[
instance instance-id
]
root primary
[
bridge-diameter
bridgenumber
[
hello-time
centi-seconds
] ]
Required