Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) - Manual (Page 455)

Multi-Service IronWare Switching Configuration Guide 425
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Convergence in a simple topology
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Now, Port3/Switch 3 is currently in a discarding state and is negotiating a port role. It received RST
BPDUs from Port3/Switch 2. The RSTP algorithm determines that the RST BPDUs Port3/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/Switch 1 and Port5/Switch 1 are physically connected. Port5/Switch 1 received RST
BPDUs that are superior to those received on Port3/Switch 1; therefore, Port5/Switch 1 is given
the Backup port role while Port3 is given the Designated port role. Port3/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 87 .
FIGURE 87 Active Layer 2 path