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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter 18 Configuring Optional Spanning-Tree Features
Configuring Optional Spanning-Tree Features
Enabling Cross-Stack UplinkFast
Before enabling CSUF, make sure your stack switches are properly connected. For more information,
see the
“Connecting the Stack Ports” section on page 18-8
.
The CSUF feature is supported only when the switch is running PVST+. It is not supported when the
switch is running rapid PVST+ or MSTP.
Beginning in privileged EXEC mode, follow these steps to enable CSUF. This procedure is optional.
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.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
spanning-tree uplinkfast [max-update-rate
pkts-per-second]
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.
Step 1
interface interface-id
Enter interface configuration mode, and specify the GBIC interface
on which to enable CSUF.
Step 2
spanning-tree stack-port
Enable CSUF on only one stack-port GBIC interface.
The stack port connects to the GigaStack GBIC 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.
Step 3
end
Return to privileged EXEC mode.
Step 4
show running-config
Verify your entries.
Step 5
copy running-config startup-config
(Optional) Save your entries in the configuration file.