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Catalyst 6500 Series Switch Cisco IOS Software Configuration Guide—Release 12.1 E
78-14099-04
Chapter 16 Configuring Optional STP Features
Enabling PortFast
To enable the default PortFast configuration, perform this task: This example shows how to enable the default PortFast configuration:
Router# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)# spanning-tree portfast default
Router(config)# ^Z
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 disabled 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
---------------------- -------- --------- -------- ---------- ----------
VLAN0001 0 0 0 1 1
VLAN0010 0 0 0 2 2
---------------------- -------- --------- -------- ---------- ----------
2 vlans 0 0 0 3 3
Router#
Router# show spanning-tree interface fastEthernet 4/4 detail
Port 196 (FastEthernet4/4) of VLAN0010 is forwarding
Port path cost 1000, Port priority 160, Port Identifier 160.196.
Designated root has priority 32768, address 00d0.00b8.140a
Designated bridge has priority 32768, address 00d0.00b8.140a
Designated port id is 160.196, designated path cost 0
Timers:message age 0, forward delay 0, hold 0
Number of transitions to forwarding state:1
The port is in the portfast mode by default
Link type is point-to-point by default
BPDU:sent 10, received 0
Router(config-if)# spanning-tree portfast trunk
%Warning:portfast should only be enabled on ports connected to a single
host. Connecting hubs, concentrators, switches, bridges, etc... to this
interface when portfast is enabled, can cause temporary bridging loops.
Use with CAUTION
Router(config-if)# ^Z
Command Purpose
Step 1 Router(config)# spanning-tree portfast default Configures the PortFast default.
Step 2 Router(config)# show spanning-tree summary totals Verifies the global configuration.
Step 3 Router(config)# show spanning-tree interface x
detail
Verifies the effect on a specific port.
Step 4 Router(config-if)# spanning-tree portfast trunk Enables the PortFast trunk on a port
Step 5 Router# show spanning-tree interface fastEthernet
x detail
Verifies the configuration.