214 CHAPTER 23: MSTP CONFIGURATION
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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-MSTI mapping table, and
revision level.
■ The 3Com series support only the MST region name, VLAN-to-MSTI mapping
table, and revision level. Switches with the settings of these parameters being
the same are assigned to the same MST region.
The configuration of MST region-related parameters, especially the
VLAN-to-instance mapping table, will cause MSTP to launch a new spanning tree
calculation process, which may result in network topology instability. To reduce the
possibility of topology instability caused by configuration, MSTP will not
immediately launch a new spanning tree calculation process when processing MST
region-related configurations; instead, such configurations will take effect only if
you:
■ activate the MST region-related parameters using the active
region-configuration command, or
■ enable MSTP using the stp enable command.
Configuration example
# Configure the MST region name to be “info”, the MSTP revision level to be 1,
and VLAN 2 through VLAN 10 to be mapped to instance 1 and VLAN 20 through
VLAN 30 to instance 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
Configure the
VLAN-to-instance
mapping table
instance instance-id vlan vlan-list Optional
Use either command.
All VLANs in an MST region
are mapped to MST
instance 0 by default.
vlan-mapping modulo modulo
Configure the MSTP
revision level of the MST
region
revision-level level Optional
0 by default
Activate MST region
configuration manually
active region-configuration Required
Display all the
configuration information
of the MST region
check region-configuration Optional
Display the currently
effective MST region
configuration information
display stp region-configuration The display command can
be executed in any view.
To do… Use the command… Remarks
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