3Com Switch 8800 Advanced Software V5 Configuration Guide

110 CHAPTER 11: MSTP CONFIGURATION
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Two device belong to the same MST region only if they are configure to have the
same MST region name, the same VLAN-to-instance mapping entries in the MST
region and the same MST region revision level, and they are interconnected via a
physical link.
The configuration of MST region-related parameters, especially the
VLAN-to-instance mapping table, will cause MSTP to launch a new spanning tree
computing 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 computing process when processing MST
region-related configurations; instead, such configurations will take effect only if
you:
■ activate the MST region-related parameters suing 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
Specifying the Root
Bridge or a Secondary
Root Bridge
MSTP can determine the root bridge of a spanning tree through MSTP computing.
Alternatively, you can specify the current device as the root bridge using the
commands provided by the system.
Configure the
VLAN-to-instance mapping
table
instance instance-id vlan
vlan-list
Optional
By default, all VLANs in an
MST region are mapped to
MST instance 0.
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 the configuration of
the current 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