Enabling Uplinkfast For Use With Redundant Links; Enabling Backbonefast - Cisco IE 3000 Software Configuration Manual
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Also See for IE 3000:
- Hardware installation manual (186 pages) ,
- Getting started manual (32 pages) ,
- Software configuration manual (874 pages)
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Chapter 18
Configuring Optional Spanning-Tree Features
Enabling UplinkFast for Use with Redundant Links
UplinkFast cannot be enabled on VLANs that have been configured with a 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.
You can configure the UplinkFast feature for rapid PVST+ or for the MSTP, but the feature remains
disabled (inactive) until you change the spanning-tree mode to PVST+.
Beginning in privileged EXEC mode, follow these steps to enable UplinkFast. This procedure is
optional.
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 reduce the chance that
a 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.
Enabling BackboneFast
You can enable BackboneFast to detect indirect link failures and to start the spanning-tree
reconfiguration sooner.
If you use BackboneFast, you must enable it on all switches in the network. BackboneFast is not
Note
supported on Token Ring VLANs. This feature is supported for use with third-party switches.
OL-13018-01
Purpose
Enter global configuration mode.
Enable UplinkFast.
(Optional) For pkts-per-second, the range is 0 to 32000 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.
Cisco IE 3000 Switch Software Configuration Guide
Configuring Optional Spanning-Tree Features
18-13
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