Enabling Uplinkfast For Use With Redundant Links - Cisco Catalyst 2950 Software Configuration Manual
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Also See for Catalyst 2950:
- Configuration manual (710 pages) ,
- Command reference manual (686 pages) ,
- Software configuration manual (674 pages)
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Chapter 12
Configuring Optional Spanning-Tree Features
To disable BPDU filtering, use the no spanning-tree portfast bpdufilter default global configuration
command.
You can override the setting of the no spanning-tree portfast bpdufilter default global configuration
command by using the spanning-tree bpdufilter enable interface configuration command.
Enabling UplinkFast for Use with Redundant Links
UplinkFast cannot be enabled on VLANs that have been configured for switch priority. To enable
UplinkFast on a VLAN with switch priority configured, first restore the switch priority on the VLAN to
the default value by using the no spanning-tree vlan vlan-id priority global configuration command.
Note
When you enable UplinkFast, it affects all VLANs on the switch. You cannot configure UplinkFast on
an individual VLAN.
The UplinkFast feature is supported only when the switch is running PVST.
Beginning in privileged EXEC mode, follow these steps to enable UplinkFast:
Command
Step 1
configure terminal
Step 2
spanning-tree uplinkfast [max-update-rate
pkts-per-second]
Step 3
end
Step 4
show spanning-tree summary
Step 5
copy running-config startup-config
When UplinkFast is enabled, the switch priority of all VLANs is set to 49152. If you change the path
cost to a value less than 3000 and you enable UplinkFast or UplinkFast is already enabled, the path cost
of all interfaces and VLAN trunks is increased by 3000 (if you change the path cost to 3000 or above,
the path cost is not altered). The changes to the switch priority and the path cost reduces the chance that
the switch will become the root switch.
When UplinkFast is disabled, the switch priorities of all VLANs and path costs of all interfaces are set
to default values if you did not modify them from their defaults.
To return the update packet rate to the default setting, use the no spanning-tree uplinkfast
max-update-rate global configuration command. To disable UplinkFast, use the no spanning-tree
uplinkfast command.
78-11380-04
Purpose
Enter global configuration mode.
Enable UplinkFast on the switch.
(Optiona) For pkts-per-second, the range is 0 to 65535 packets per
second; the default is 150.
If you set the rate to 0, station-learning frames are not generated,
and the spanning-tree topology converges more slowly after a loss
of connectivity.
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
Catalyst 2950 Desktop Switch Software Configuration Guide
Configuring Optional Spanning-Tree Features
12-17
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Troubleshooting
