Switch 7700 Command reference Guide, v2.0

RSTP Configuration Commands 311
CAUTION: In a switching network, you can configure no more than one primary
root for a spanning tree but you can configure one or more secondary roots for it.
Remember not to designate more than one primary root in a spanning tree;
otherwise, the calculation result will be unpredictable. After a switch is configured
as primary root switch or secondary root switch, user can’t modify the bridge
priority of the switch.
Example
Designate the current switch as the primary root of a spanning tree.
[SW7700]stp root primary
stp root secondary Syntax
stp root secondary
undo stp root
View
System view
Parameter
None
Description
Using the stp root secondary command, you can configure the current switch
as a secondary root of a specified spanning tree. Using the
undo stp root
secondary
command, you can cancel the designation of the current switch for a
secondary root of a specified spanning tree.
By default, a switch is not a secondary root.
You can designate one or more secondary root for a spanning tree. When the
primary root fails or is powered off, a secondary root can take its place. Of more
than one secondary roots, the one with the smallest MAC address will become the
primary root of the specified spanning tree.
You can configure no more than one primary root for a spanning tree but you can
configure one or more secondary roots for it. You cannot change the bridge
priority of a switch if you configure it as secondary root of a spanning tree.
After a switch is configured as primary root switch or secondary root switch, user
can’t modify the bridge priority of the switch.
Example
Designate the current switch as a secondary root of the STP.
[SW7700]stp root secondary
stp root-protection Syntax
stp root-protection
undo stp root-protection