CLI Reference Guide

202 CHAPTER 5: CONFIGURING WX SYSTEM AND ADMINISTRATIVE PARAMETERS
Backbone Fast Convergence Backbone fast convergence accelerates
a port’s recovery following the failure of an indirect link. Normally, when
a forwarding link fails, a bridge that is not directly connected to the link
does not detect the link change until the maximum age timer expires.
Backbone fast convergence enables the WX switch to listen for bridge
protocol data units (BPDUs) sent by a designated bridge when the
designated bridge’s link to the root bridge fails, and immediately verifies
whether BPDU information stored on a port is still valid. If the BPDU
information on the port is no longer valid, the bridge immediately starts
the listening stage on the port.
If you plan to use the backbone fast convergence feature, you must
enable it on all the bridges in the spanning tree.
CAUTION: The backbone fast convergence feature is not compatible
with switches that are running standard IEEE 802.1D Spanning Tree
implementations. This includes switches running Rapid Spanning Tree or
Multiple Spanning Tree.
Uplink Fast Convergence Uplink fast convergence enables a WX
switch that has redundant links to the network core to immediately
change the state of a backup link to forwarding if the primary link to the
root fails. Uplink fast convergence bypasses the listening and learning
states to immediately enter the forwarding state.
The uplink fast convergence feature is applicable to bridges that are
acting as access switches to the network core (distribution layer) but are
not in the core themselves. Do not enable the feature on WX switches
that are in the network core.
To configure fast convergence features:
1 In the Organizer panel, navigate to the WX switch you want to configure.
2 Expand the switch to see the configuration options.
3 Select Spanning Tree Properties.
4 Select Config > Edit. The Modify Spanning Tree Properties dialog box
appears.
5 To switch to an alternate port when the root port fails, select Enable
Uplink Fast.
6 To enable the backbone fast convergence feature, select Enable
Backbone Fast.