HP ProCurve 9304M Installation And Configuration Manual page 247

Now, Port3/Routing Switch 3 is currently in a discarding state and is negotiating a port role. It received RST
BPDUs from Port3/Routing Switch 2. The 802.1W algorithm determines that the RST BPDUs Port3/Routing
Switch 3 received are superior to those it can transmit; however, they are not superior to those that are currently
being received by the current Root port (Port4). Therefore, Port3 retains the role of Alternate port.
Ports 3/Routing Switch 1 and Port5/Routing Switch 1 are physically connected. Port5/Routing Switch 1 received
RST BPDUs that are superior to those received on Port3/Routing Switch 1; therefore, Port5/Routing Switch 1 is
given the Backup port role while Port3 is given the Designated port role. Port3/Routing Switch 1, does not go
directly into a forwarding state. It waits until the forward delay time expires twice on that port before it can proceed
to the forwarding state.
Once convergence is achieved, the active Layer 2 forwarding path converges as shown in Figure 8.16.
Figure 8.16 Active Layer 2 Path
Routing Switch 1
Bridge priority = 1000
Port3
Port2
Port3
Routing Switch 3
Bridge priority = 300
Configuring Spanning Tree Protocol (STP) and Advanced STP Features
Routing Switch 2
Bridge priority = 200
Port7
Port2 Port2
Port3
Port3
Port4 Port4
Routing Switch 4
Bridge priority = 400
Indicates the active Layer 2 path
Port8
Bridge priority = 60
Port5
Port2
Port4
Port4
Port5 Port5
Bridge priority = 900
Routing Switch 5
Port3
Port3
Routing Switch 6
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