Configuring UplinkFast 573

Configuring UplinkFast
When configuring UplinkFast, remember that all VLANs on the switch are affected and that
you cannot configure UplinkFast on individual VLANs.
To configure UplinkFast on a set-based switch, use the set spantree uplinkfast command:
Terry_4000> (enable) set spantree uplinkfast ?
Usage: set spantree uplinkfast <enable> [rate <station_ update_rate>]
[all-protocols <off|on>]
set spantree uplinkfast <disable>
The options are really just enable or disable. The station update rate value is the number
of multicast packets transmitted per 100 milliseconds (by default, it is set to 15 packets per millisecond).
It is not recommended that you change this value.
The switch provides an output describing what the command changed on the switch, as
shown here:
Terry_4000> (enable) set spantree uplinkfast enable
VLANs 1-1005 bridge priority set to 49152.
The port cost and portvlancost of all ports set to above 3000.
Station update rate set to 15 packets/100ms.
uplinkfast all-protocols field set to off.
uplinkfast enabled for bridge.
Terry_4000> (enable)
The VLAN priorities are automatically changed to 49152, and the port costs are set to above
3000. These are changed to make it unlikely that the switch will become the root switch.
You can verify the UplinkFast configuration with the show spantree uplinkfast command:
Terry_4000> (enable) show spantree uplinkfast
Station update rate set to 15 packets/100ms.
uplinkfast all-protocols field set to off.
VLAN port list
-----------------------------------------------
1 1/1(fwd)
2 1/1(fwd)
3 1/1(fwd)
4 1/1(fwd)
Terry_4000> (enable)
Notice that all four VLANs

Notice that all four VLANs are changed and that we were not asked which VLANs to run
UplinkFast on.
Using Redundant Links with STP 531
To configure UplinkFast on an IOS-based switch, use the command spanning-tree
uplinkfast in global configuration mode:
Terry_2950(config)#spanning-tree ?
backbonefast Enable BackboneFast Feature
etherchannel Spanning tree etherchannel specific configuration
extend Spanning Tree 802.1t extensions
loopguard Spanning tree loopguard options
mode Spanning tree operating mode
pathcost Spanning tree pathcost options
portfast Spanning tree portfast options
uplinkfast Enable UplinkFast Feature
vlan VLAN Switch Spanning Tree
Terry_2950(config)#spanning-tree uplinkfast ?
max-update-rate Rate at which station address updates are sent
<cr>
Terry_2950(config)#spanning-tree uplinkfast
Terry_2950(config)#
To verify that UplinkFast is configured and running, use the command show spanningtree
uplinkfast:
Terry_2950#show spanning-tree uplinkfast
UplinkFast is enabled
Station update rate set to 150 packets/sec.
UplinkFast statistics
-----------------------
Number of transitions via uplinkFast (all VLANs) : 0
Number of proxy multicast addresses transmitted (all VLANs) : 0
Name Interface List
-------------------- ------------------------------------
VLAN0001
VLAN0002
VLAN0003
Terry_2950
The default frame generation rate is 150pps, which is displayed with the show uplink-fast
command. The next command used to help STP maintain a consistent network is BackboneFast.