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Software Configuration Guide—Release 12.2(25)SG
OL-7659-03
Chapter14 Configuring STP Features
Enabling BackboneFast
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
Step1 Switch(config)# [no] spanning-tree backbonefast Enables BackboneFast.
You can use the no keyword to disable BackboneFast.
Step2 Switch(config)# end Exits configuration mode.
Step3 Switch# show spanning-tree backbonefast Verifies that BackboneFast is enabled.