Enabling Backbonefast - Cisco Catalyst 2950 Software Configuration Manual

Chapter 15 Configuring Optional Spanning-Tree Features
Beginning in privileged EXEC mode, follow these steps to enable CSUF. This procedure is optional.
Command
Step 1 configure terminal
Step 2 spanning-tree uplinkfast [max-update-rate
pkts-per-second]
Step 3
interface interface-id
Step 4 spanning-tree stack-port
Step 5
end
Step 6 show running-config
Step 7
copy running-config startup-config
To disable CSUF on an interface, use the no spanning-tree stack-port interface configuration
command. To disable UplinkFast on the switch and all its VLANs, use the no spanning-tree uplinkfast
global configuration command.

Enabling BackboneFast

You can enable BackboneFast to detect indirect link failures and to start the spanning-tree
reconfiguration sooner.
Note If you use BackboneFast, you must enable it on all switches in the network. BackboneFast is not
supported on Token Ring VLANs. This feature is supported for use with third-party switches.
You can enable the BackboneFast feature for rapid PVST+ or for the MSTP, but the feature remains
disabled (inactive) until you change the spanning-tree mode to PVST+.
78-11380-12
Purpose
Enter global configuration mode.
Enable UplinkFast on the switch.
(Optional) For max-update-rate pkts-per-second, specify the
number of packets per second at which update packets are sent. The
range is 0 to 65535; the default is 150 packets per second.
Specify the GBIC module interface on which to enable CSUF, and
enter interface configuration mode.
Enable CSUF on only one stack-port GBIC interface.
The stack port connects to the GigaStack GBIC module multidrop
backbone. If you try to enable CSUF on a Fast Ethernet or a
Gigabit-capable Ethernet port, you receive an error message.
If CSUF is already enabled on an interface and you try to enable it
on another interface, you receive an error message. You must disable
CSUF on the first interface before enabling it on a new interface.
Use this command only on access switches.
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
Configuring Optional Spanning-Tree Features
15-19