shutdown
Dell(conf-if-te-2/0)#
Influencing RSTP Root Selection
RSTP determines the root bridge, but you can assign one bridge a lower priority to increase the likelihood
that it is selected as the root bridge.
To change the bridge priority, use the following command.
• Assign a number as the bridge priority or designate it as the primary or secondary root.
PROTOCOL SPANNING TREE RSTP mode
bridge-priority priority-value
–priority-value The range is from 0 to 65535. The lower the number assigned, the more likely
this bridge becomes the root bridge.
The default is 32768. Entries must be multiples of 4096.
Example of the bridge-priority Command
A console message appears when a new root bridge has been assigned. The following example example
shows the console message after the bridge-priority command is used to make R2 the root bridge
(shown in bold).
Dell(conf-rstp)#bridge-priority 4096
04:27:59: %RPM0-P:RP2 %SPANMGR-5-STP_ROOT_CHANGE: RSTP root changed. My Bridge
ID:
4096:0001.e80b.88bd Old Root: 32768:0001.e801.cbb4 New Root: 4096:0001.e80b.88bd
SNMP Traps for Root Elections and Topology Changes
To enable SNMP traps for RSTP, MSTP, and PVST+ collectively, use the following command.
Enable SNMP traps for RSTP, MSTP, and PVST+ collectively.
snmp-server enable traps xstp
Configuring Fast Hellos for Link State Detection
To achieve sub-second link-down detection so that convergence is triggered faster, use RSTP fast hellos.
The standard RSTP link-state detection mechanism does not offer the same low link-state detection
speed.
RSTP fast hellos decrease the hello interval to the order of milliseconds and all timers derived from the
hello timer are adjusted accordingly. This feature does not inter-operate with other vendors, and is
available only for RSTP.
• Configure a hello time on the order of milliseconds.
PROTOCOL RSTP mode
hello-time milli-second interval
Rapid Spanning Tree Protocol (RSTP) 779