Extreme Networks ExtremeWare XOS Guide Manual page 444

Spanning Tree Protocol
As shown in
Regards itself as the new root bridge.
●
Sends BPDU messages on both of its designated ports to bridges F and D, respectively.
●
Figure 41: New root bridge selected
3 As shown in
bridge E, bridge F:
Decides that the receiving port is the root port.
●
Determines that bridge E is the root bridge.
●
Figure 42: Communicating new root bridge status to neighbors
4 Bridge D believes that bridge A is the root bridge. When bridge D receives the BPDU from bridge E
on its alternate port, bridge D:
Immediately begins the max age timer on its alternate port.
●
Performs a configuration update.
●
444
Figure 41, after the configuration update, bridge E:
A
A , 0
F
F , 0
Figure 42, when bridge F receives the superior BPDU and configuration update from
A
A , 0
F
E , 1
B C
A , 1 A , 2
Designated
port
E D
E , 0 A , 3
BPDU
B C
A , 1 A , 2
Designated
port
E D
E , 0 A , 3
Root
port
EX_055c
Root
port
EX_055d
ExtremeWare XOS 11.3 Concepts Guide