Specifying The Root Bridge Or A Secondary Root Bridge - 3Com MSR 50 Series Configuration Manual

460 C 23: MSTP C
HAPTER
n
Specifying the Root
Bridge or a Secondary
Root Bridge
ONFIGURATION
To do...
Configure the
VLAN-to-instance mapping
table
Configure the MSTP revision
level of the MST region
Activate MST region
configuration manually
Display all the configuration
information of the MST region
Display the currently effective
MST region configuration
information
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
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.
Use the command...
instance instance-id vlan
vlan-list
vlan-mapping modulo
modulo
revision-level level
active region-configuration Required
check region-configuration Optional
display stp
region-configuration
Remarks
Optional
Use either command
All VLANs in an MST region
are mapped to MST instance
0 by default.
Optional
0 by default
Optional
The display command can be
executed in any view