Command Line Reference Guide

Per-VLAN Spanning Tree plus (PVST+) | 801
Defaults
Not Configured
Command Modes
INTERFACE
Command
History
Usage
Information
The BPDU guard option prevents the port from participating in an active STP topology in case a
BPDU appears on a port unintentionally, or is mis-configured, or is subject to a DOS attack. This
option places the port into an error disable state if a BPDU appears, and a message is logged so that the
administrator can take corrective action.
If shutdown-on-violation is not enabled, BPDUs will still be sent to the RPM CPU.
Example
Figure 31-6. spanning-tree pvst vlan Command Example
cost number (OPTIONAL) Enter the keyword cost followed by the port cost value.
Range: 1 to 200000
Defaults:
100 Mb/s Ethernet interface = 200000
1-Gigabit Ethernet interface = 20000
10-Gigabit Ethernet interface = 2000
Port Channel interface with one 100 Mb/s Ethernet = 200000
Port Channel interface with one 1-Gigabit Ethernet = 20000
Port Channel interface with one 10-Gigabit Ethernet = 2000
Port Channel with two 1-Gigabit Ethernet = 18000
Port Channel with two 10-Gigabit Ethernet = 1800
Port Channel with two 100-Mbps Ethernet = 180000
priority value (OPTIONAL) Enter the keyword priority followed the Port priority value in
increments of 16.
Range: 0 to 240
Default: 128
Version 8.3.5.0 Introduced on S55
Version 8.2.1.0 Introduced hardware shutdown-on-violation option
Version 7.6.1.0 Support added for S-Series
Version 7.5.1.0 Support added for C-Series
Version 7.4.1.0 Added the optional Bridge Port Data Unit (BPDU) guard
Version 6.2.1.1 Introduced
Note: A port configured as an edge port, on a PVST switch, will immediately transition to
the forwarding state. Only ports connected to end-hosts should be configured as an edge port.
Consider an edge port similar to a port with a spanning-tree portfast enabled.
Force10(conf-if-gi-1/1)#spanning-tree pvst vlan 3 cost 18000
Force10(conf-if-gi-1/1)#end
Force10(conf-if-gi-1/1)#show config
!
interface GigabitEthernet 1/1
no ip address
switchport
spanning-tree pvst vlan 3 cost 18000
no shutdown
Force10(conf-if-gi-1/1)#end
Force10#