Extreme Networks ExtremeWare XOS Guide - Page 445

Rapid Spanning Tree Protocol
ExtremeWare XOS 11.3 Concepts Guide
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As shown in Figure 43, after the configuration update, bridge D:
● Moves the alternate port to a designated port.
● Sends a “propose” message to bridge E to solicit confirmation of its designated role and to
rapidly move the port into the designated state.
Figure 43: Sending a propose message to confirm a port role
5 Upon receiving the proposal, bridge E (as shown in Figure 44):
● Performs a configuration update.
● Changes its receiving port to a root port.
The existing designated port enters the blocking state.
Bridge E then sends:
● A “propose” message to bridge F.
● An “agree” message from its root port to bridge D.
Figure 44: Communicating port status to neighbors
EX_055e
B
A , 1
C
A , 2
E
E , 0
Propose BPDU
A
A , 0
F
E , 1
D
A , 3
Designated
port
Root
port
EX_055f
B
A , 1
C
A , 2
E
A , 4
Agree BPDU
A
A , 0
F
E , 1
D
A , 3
Designated
port
Root
port