Configuring Spanning Tree Protocol (STP) and IronSpan Features
December 2005 © Foundry Networks, Inc. 7 - 25
• Sync – Once the Root port is elected, it sets a sync signal on all the ports on the bridge. The signal tells the
ports to synchronize their roles and states (Figure 7.5). Ports that are non-edge ports with a role of
Designated port change into a discarding state. These ports have to negotiate with their peer ports to
establish their new roles and states.
Figure 7.5 Sync Stage
BigIron
Switch 200
Switch 300
Port1
Designated port
Port1
Root port
Sync
Port2
Sync
Discarding
Port2
Port3
Port3
Sync
Discarding
Indicates a signal
Switch 100
Root Bridge
Switch 400