Cisco Systems WSC4500X16SFP Manual De Usuario

14-15

Software Configuration Guide—Release 12.2(25)SG

OL-7659-03

Chapter 14 Configuring STP Features

Enabling BackboneFast

Note

For BackboneFast to work, you must enable it on all switches in the network. BackboneFast is supported
for use with third-party switches but it is not supported on Token Ring VLANs.

To enable BackboneFast, perform this task:

This example shows how to enable BackboneFast:

Switch(config)# spanning-tree backbonefast

Switch(config)# end

Switch#

This example shows how to verify that BackboneFast is enabled:

Switch# show spanning-tree backbonefast

BackboneFast is enabled

BackboneFast statistics

-----------------------

Number of transition via backboneFast (all VLANs) : 0

Number of inferior BPDUs received (all VLANs) : 0

Number of RLQ request PDUs received (all VLANs) : 0

Number of RLQ response PDUs received (all VLANs) : 0

Number of RLQ request PDUs sent (all VLANs) : 0

Number of RLQ response PDUs sent (all VLANs) : 0

Switch#

This example shows how to display a summary of port states:

Switch#show spanning-tree summary

Root bridge for:VLAN0001, VLAN1002-VLAN1005

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

EtherChannel misconfiguration guard is enabled

UplinkFast is enabled

BackboneFast is enabled

Pathcost method used is short

Name Blocking Listening Learning Forwarding STP Active

---------------------- -------- --------- -------- ---------- ----------

VLAN0001 0 0 0 3 3

VLAN1002 0 0 0 2 2

VLAN1003 0 0 0 2 2

VLAN1004 0 0 0 2 2

VLAN1005 0 0 0 2 2

---------------------- -------- --------- -------- ---------- ----------

Command

Purpose

Step 1

Switch(config)# [no] spanning-tree backbonefast

Enables BackboneFast.

You can use the no keyword to disable BackboneFast.

Step 2

Switch(config)# end

Exits configuration mode.

Step 3

Switch# show spanning-tree backbonefast

Verifies that BackboneFast is enabled.