Configuring Uplinkfast; Enabling Uplinkfast - Cisco WS-C2948G-GE-TX Configuration Manual

Chapter 8 Configuring Spanning Tree PortFast, BPDU Guard, BPDU Filter, UplinkFast, BackboneFast, and Loop Guard

Configuring UplinkFast

The following sections describe how to configure the UplinkFast feature on the switch.

Enabling UplinkFast

When you enable UplinkFast on the switch, UplinkFast processing is enabled and the spanning tree
bridge priority for all VLANs is set to 49,152, making it unlikely that the switch will become the root
switch. The spanning tree port cost and port-VLAN cost of all ports on the switch is increased by 3000.
The station_update_rate value in the UplinkFast command represents the number of dummy multicast
packets that are transmitted per 100 ms (the default is 15 packets per 100 ms) in the event of a direct link
failure.
Enter the all-protocols on keywords on switches that have UplinkFast enabled, but do not have protocol
filtering enabled, and that are connected to upstream switches in the network that have protocol filtering
enabled. The all-protocols on keywords cause the switch to generate multicasts for each
protocol-filtering group.
On switches with both UplinkFast and protocol filtering enabled, or if no other switches have protocol
filtering enabled, you do not need to use the all-protocols on keywords.
Note When you enable UplinkFast, it affects all VLANs on the switch. You cannot configure UplinkFast on a
per-VLAN basis.
To enable UplinkFast, perform this task in privileged mode:
Task
Step 1 Enable UplinkFast on the switch.
Step 2 Verify that UplinkFast is enabled.
This example shows how to enable UplinkFast with a station-update rate of 40 packets per 100 ms and
verify that UplinkFast is enabled:
Console> (enable) set spantree uplinkfast enable rate 40
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 40 packets/100ms.
uplinkfast all-protocols field set to off.
uplinkfast enabled for bridge.
Console> (enable) show spantree uplinkfast
Station update rate set to 40 packets/100ms.
uplinkfast all-protocols field set to off.
VLAN
-----------------------------------------------
1
100
521
522
523
524
Console> (enable)
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2948G-GE-TX, and Catalyst 2980G Switches Software Configuration Guide—Release 8.2GLX
78-15908-01
port list
1/1(fwd),1/2
1/2(fwd)
1/1(fwd),1/2
1/1(fwd),1/2
1/1(fwd),1/2
1/1(fwd),1/2
Command
set spantree uplinkfast enable [rate station_update_rate]
[all-protocols {off | on}]
show spantree uplinkfast [vlans]
Configuring UplinkFast
8-15