3Com 5500-SI - Setting the Switch as the Root;Secondary Root Bridge

170 CHAPTER 13: MSTP CONFIGURATION
Configuration example
1 Configure an MST region, with the name being 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.
<S5500> system-view
System View: return to User View with Ctrl+Z.
[S5500] stp region-configuration
[S5500-mst-region] region-name info
[S5500-mst-region] instance 1 vlan 2 to 10
[S5500-mst-region] instance 2 vlan 20 to 30
[S5500-mst-region] revision-level 1
[S5500-mst-region] active region-configuration
2 Verify the above configuration.
[S5500-mst-region] check region-configuration
Admin configuration
Format selector :0
Region name :info
Revision level :1
Instance Vlans Mapped
0 11 to 19, 31 to 4094
1 1 to 10
2 20 to 30
Setting the Switch as
the Root/Secondary
Root Bridge
MSTP can determine the root bridge of a spanning tree by calculating. In addition,
you can specify a switch to be the root bridge by using the corresponding commands.
Setting a switch as the root bridge of a spanning tree
Setting a switch as a secondary root bridge of a spanning tree
Using the stp root primary/stp root secondary command, you can specify a switch
to be the root bridge or a secondary root bridge of the spanning tree instance
identified by the instance-id argument. If the value of the instance-id argument is 0,
the two commands specify the current switch to be the root bridge or a secondary
root bridge of the CIST.
A switch can play different roles in different spanning tree instances independently at
the same time. However, in one spanning tree instance, a switch cannot be the root
bridge and a secondary root bridge simultaneously.
Table 143 Set a switch as the root bridge of a specified spanning tree
Operation Command Description
Enter system view system-view -
Set the switch as the root
bridge of a specified
spanning tree
stp [ instance instance-id ] root primary
[ bridge-diameter bridgenum ] [
hello-time centi-seconds ]
Required
Table 144 Set a switch as a secondary root bridge of a spanning tree
Operation Command Description
Enter system view system-view -
Set the current switch as a
secondary root bridge of a
specified spanning tree
stp [ instance instance-id ] root
secondary [ bridge-diameter
bridgenum ] [ hello-time centi-seconds ]
Required