H3C Technologies H3C S3100 Series Switches - Manual (Page 187)

Operation Manual – MSTP
H3C S3100-52P Ethernet Switch
Chapter 1 MSTP Configuration
1-12
You can specify the network diameter and the hello time parameters while configuring a
root bridge/secondary root bridge. Refer to section 1.2.8 “Configuring the Network
Diameter of the Switched Network” and 1.2.9 “Configuring the MSTP Time-related
Parameters” for information about the network diameter parameter and the hello time
parameter.
Note:
z
You can configure a switch as the root bridges of multiple spanning tree instances.
But you cannot configure two or more root bridges for one spanning tree instance.
So, do not configure root bridges for the same spanning tree instance on two or
more switches using the stp root primary command.
z
You can configure multiple secondary root bridges for one spanning tree instance.
That is, you can configure secondary root bridges for the same spanning tree
instance on two or more switches using the stp root secondary command.
z
You can also configure the current switch as the root bridge by setting the priority of
the switch to 0. Note that once a switch is configured as the root bridge or a
secondary root bridge, its priority cannot be modified.
III. Configuration example
# Configure the current switch as the root bridge of spanning tree instance 1 and a
secondary root bridge of spanning tree instance 2.
system-view
[H3C] stp instance 1 root primary
[H3C] stp instance 2 root secondary
1.2.4 Configuring the Bridge Priority of the Current Switch
Root bridges are selected according to the bridge priorities of switches. You can make
a specific switch be selected as a root bridge by setting a lower bridge priority for the
switch. An MSTP-enabled switch can have different bridge priorities in different
spanning tree instances.