Brocade TurboIron 24X Series Configuration Guide - Manual (Page 583)

Brocade TurboIron 24X Series Configuration Guide 549
53-1003053-01
Configuring STP related features
After convergence is complete, Figure 82 shows the active Layer 2 path of the topology in
Figure 81 .
FIGURE 82 Active Layer 2 path in complex topology
Propagation of topology change
The Topology Change state machine generates and propagates the topology change notification
messages on each port. When a Root port or a Designated port goes into a forwarding state, the
Topology Change state machine on those ports send a topology change notice (TCN) to all the
bridges in the topology to propagate the topology change.
NOTE
Edge ports, Alternate ports, or Backup ports do not need to propagate a topology change.
The TCN is sent in the RST BPDU that a port sends. Ports on other bridges in the topology then
acknowledge the topology change once they receive the RST BPDU, and send the TCN to other
bridges until all the bridges are informed of the topology change.
Bridge priority = 1000
Bridge priority = 200
Bridge priority = 60
Bridge priority = 300 Bridge priority = 400 Bridge priority = 900
Port3
Port3
Port3
Port3 Port3
Port3
Port2 Port2
Port2
Port2
Port4 Port4
Port4
Port4
Port5
Port5 Port5
Port7 Port8
Indicates the active Layer 2 path
Switch 1
Switch 3 Switch 4 Switch 6
Switch 5 Switch 2