3com 3CRWX120695A WXR100 Manual De Usuario

The standard STP timers delay traffic forwarding briefly after a topology 
change. The time a port takes to change from the listening state to the 
learning state or from the learning state to the forwarding state is called 
the forwarding delay. In some configurations, this delay is unnecessary. 

The WX switch provides the following fast convergence features to 
bypass the forwarding delay: 

„

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 If the BPDU information on the port is no longer valid, the 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.

„

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.

To enable fast convergence features:

1 Access the VLAN table:

a Select the Configuration tool bar option.

b In the Organizer panel, click the plus sign next to the WX switch. 

c Click the plus sign next to System.

d Select VLANs.