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Catalyst 2950 Desktop Switch Software Configuration Guide
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Chapter 13 Configuring Optional Spanning-Tree Features
Configur ing Optiona l Spanning-Tree Features

Enabling Cross-Stack UplinkFast

Before ena bling CSU F, make sure your sta ck switch es are proper ly connec ted. For more informat ion,
see th e Connec ting the Stack Ports sect ion on page 13-8 .
The CSU F f eature is sup por ted on ly whe n t he sw itch is r unn ing PVST.
Beginning in privileged EXEC mode, follow these steps to enable CSUF:
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-tr ee uplinkf ast
global configurat ion comm and.
Command Purpose
Step 1 configure terminal Enter g l obal c onfigura tion m od e.
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
numbe r of packet s per seco nd at which upd ate pack ets are sent. The
range is 0 to 655 35; the defaul t is 150 p ackets per sec ond .
Step 1 int er fa ce interface-id Enter interf ace configuratio n mode, an d specify the GBIC inter fa ce
on which to enable CSUF.
Step 2 spanning-tree stack-port Enable CSUF on only one stac k-por t GBIC interfac e.
The stack port conne cts to th e GigaStack G BIC multid rop
backbo ne . If yo u tr y to e na ble CSUF o n a Fast Et herne t o r a
Gigab it- capa ble E the rnet po rt, yo u re ce ive an err or messa ge.
If CSU F i s a lre ady en ab led on an i n terfa ce a nd yo u tr y to e nab le 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 yo ur entri es.
Step 5 copy running-config startup-config (Optio nal) Save your e ntr ies in the con figurati on file.