FTOS Configuration Guide for the C-Series - Force10 Networks

FTOS Behavior: BPDU Guard and BPDU filtering (see Removing an Interface from the Spanning
Tree Group on page 390) both block BPDUs, but are two separate features.
BPDU Guard:
• is used on edgeports and blocks all traffic on edgeport if it receives a BPDU
• drops the BPDU after it reaches the RPM and generates a console message
BPDU Filtering:
• disables Spanning Tree on an interface
• drops all BPDUs at the line card without generating a console message
Influencing STP Root Selection
The Spanning Tree Protocol determines the root bridge, but you can assign one bridge a lower priority to
increase the likelihood that it will be selected as the root bridge. You can also specify that a bridge is the
root or the secondary root.
To change the bridge priority or specify that a bridge is the root or secondary root:
Task Command Syntax Command Mode
Assign a number as the bridge priority or designate it as
the root or secondary root.
priority-value range: 0 to 65535. The lower the number
assigned, the more likely this bridge will become the
root bridge. The default is 32768.
• The primary option specifies a bridge priority of
8192.
• The secondary option specifies a bridge priority of
16384.
bridge-priority {priority-value |
primary | secondary}
View only the root information using the show spanning-tree root command (see Figure 275) from
EXEC privilege mode.
R1#show spanning-tree 0 root
Root ID Priority 32768, Address 0001.e80d.2462
We are the root of the spanning tree
Root Bridge hello time 2, max age 20, forward delay 15
R1#
Figure 275 show spanning-tree root Command Example
PROTOCOL
SPANNING TREE
SNMP Traps for Root Elections and Topology Changes
• Enable SNMP traps for Spanning Tree state changes using the command snmp-server enable traps
stp.
• Enable SNMP traps for RSTP, MSTP, and PVST+ collectively using the command snmp-server
enable traps xstp.
FTOS Configuration Guide, version 7.7.1.0 395