Specifying The Switch As A Primary Or A Secondary Root Bridge - H3C S9500 Series Operation Manual

Operation Manual – STP
H3C S9500 Series Routing Switches
Table 1-4 Activate the MST region configuration and exit the MST region view
Show the configuration information of the MST
region under revision
Manually activate the MST region configuration
Exit MST region view

1.2.2 Specifying the Switch as a Primary or a Secondary Root bridge

MSTP can determine the spanning tree root through calculation. You can also specify
the current switch as the root, using the command provided by the switch.
You can use the following commands to specify the current switch as the primary or
secondary root of the spanning tree.
Perform the following configuration in system view.
Table 1-5 Specify the switch as a primary or a secondary root bridge
Specify the current switch as the
primary root bridge of the specified
spanning tree
Specify the current switch as the
secondary
specified spanning tree
Specify current switch not to be the
primary or secondary root
After a switch is configured as the primary root bridge or the secondary root bridge,
users cannot modify the bridge priority of the switch.
You can configure the current switch as the primary or secondary root bridge of the STI
(specified by the instance instance-id parameter). If the instance-id takes 0, the current
switch is specified as the primary or secondary root bridge of the CIST.
The root types of a switch in different STIs are independent of one another. The switch
can be a primary or secondary root of any STI. However, it cannot serve as both the
primary and secondary roots of one STI.
If the primary root is down or powered off, the secondary root will take its place, unless
you configure a new primary root. Of two or more configured secondary root bridges,
MSTP selects the one with the smallest MAC address to take the place of the failed
primary root.
Operation
Operation
root bridge of the
1-15
Chapter 1 MSTP Region-configuration
check region-configuration
active region-configuration
quit
Command
stp [ instance instance-id ] root primary
[ bridge-diameter bridgenum ] [ hello-time
centi-senconds ]
stp [ instance instance-id ] root secondary
[ bridge-diameter bridgenum ] [ hello-time
centi-senconds ]
undo stp [ instance instance-id ] root
Command