3Com Switch 7750 Series
Command Reference Guide – MSTP Chapter 1 MSTP Configuration Commands
1-38
And you can modify the three settings after entering MST region view by using the stp
region-configuration command.
Example
# Enter MST region view.
<3Com> system-view
System View: return to User View with Ctrl+Z.
[3Com] stp region-configuration
[3Com-mst-region]
1.1.36 stp root primary Syntax
stp [ instance instance-id ] root primary [ bridge-diameter bridgenum ] [ hello-time
centi-seconds ]
undo stp [ instance instance-id ] root
View
System view
Parameter
instance-id: Spanning tree instance ID ranging from 0 to 16. A value of 0 specifies the
CIST.
bridgenum: Network diameter of the specified spanning tree. This argument ranges
from 2 to 7 and defaults to 7.
centi-seconds: Hello time (in centiseconds) of the specified spanning tree. This
argument ranges from 100 to 1,000 and defaults to 200.
Description
Use the stp root primary command to configure the current switch as the root bridge
of a specified spanning tree instance.
Use the undo stp root command to cancel the current configuration.
By default, a switch is not configured as a root bridge.
If you do not specify the instance-id argument, these two commands apply to the CIST.
You can specify the current switch as the root bridge of a spanning tree instance
regardless of the priority of the switch. You can also specify the network diameter of the
switched network by using the stp root primary command. The switch will then figure
out the following three time parameters: Hello time, Forward delay, and Max age. As
the Hello time figured out by the network diameter is not always the optimal one, you
can set it manually through the hello-time centi-seconds parameter. Normally, you are