Dell PowerConnect B-RX Configuration Manual page 436

13
State machines
FIGURE 47
Switch 300
The handshake that occurs between Switch 60 and Switch 100 follows the one described in the
previous section
becomes a non-root bridge and establishes a Root port
However, since Switch 200 already had a Root port in a forwarding state, RSTP uses the Proposing
-> Proposed -> Sync and Reroot -> Sync and Rerooted -> Rerooted and Synced -> Agreed
handshake:
•
364
Addition of a new root bridge
Switch 100
Switch 200
Port2
Port2
("Handshake when no root port is elected"
Proposing and Proposed – The Designated port on the new root bridge (Port4/Switch 60)
sends an RST BPDU that contains a proposing signal to Port4/Switch 200 to inform the port
that it is ready to put itself in a forwarding state
the RST BPDU that Port4/Switch 200 received is superior to what it can generate, so
Port4/Switch 200 assumes a Root port role.
Port2
Port1
Designated port
Port1
Root port
Port4
Port3
Port3
Switch 400
(Figure
(Figure
Port2
Designated
port
Port4
Designated port
on page 359). The former root bridge
48).
48). RSTP algorithm determines that
BigIron RX Series Configuration Guide
Switch 60
53-1001986-01