Cisco Systems 4500 Enabling PortFast BPDU Filtering

21-10
Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 21 Configuring Optional STP Features
Enabling PortFast BPDU Filtering
When you enable PortFast BPDU filtering globally and set the port configuration as the default for
PortFast BPDU filtering (see the “Enabling BackboneFast” section on page 21-16), PortFast enables or
disables PortFast BPDU filtering.
If the port configuration is not set to default, then the PortFast configuration does not affect PortFast
BPDU filtering. Table 21-1 lists all the possible PortFast BPDU filtering combinations. PortFast BPDU
filtering allows access ports to move directly to the forwarding state as soon as the end hosts are
connected.
Enabling PortFast BPDU Filtering
To enable PortFast BPDU filtering globally, perform this task:
This example shows how to enable PortFast BPDU filtering on a port:
Switch(config)# spanning-tree portfast bpdufilter default
Switch(config)# Ctrl-Z
This example shows how to verify the BPDU configuration in PVST+ mode:
Switch# show spanning-tree summary totals
Root bridge for:VLAN0010
EtherChannel misconfiguration guard is enabled
Extended system ID is disabled
Portfast is enabled by default
PortFast BPDU Guard is disabled by default
Portfast BPDU Filter is enabled by default
Loopguard is disabled by default
UplinkFast is disabled
BackboneFast is disabled
Pathcost method used is long
Name Blocking Listening Learning Forwarding STP Active
---------------------- -------- --------- -------- ---------- ----------
2 vlans 0 0 0 3 3
Switch#
Table 21-1 PortFast BPDU Filtering Port Configurations
Per-Port Configuration Global Configuration PortFast State PortFast BPDU Filtering State
Default Enable Enable Enable1
1. The port transmits at least 10 BPDUs. If this port receives any BPDUs, then PortFast and PortFast BPDU filtering are
disabled.
Default Enable Disable Disable
Default Disable Not applicable Disable
Disable Not applicable Not applicable Disable
Enable Not app licab le Not applicable Enable
Command Purpose
Step 1 Switch(config)# spanning-tree portfast bpdufilter default Enables BPDU filtering globally on the
switch.
Step 2 Switch# show spanning-tree summary totals Verifies the BPDU configuration.