Configuration Guide User guide

FastIron Configuration Guide 1121
53-1002494-02
STP feature configuration
• 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 (Figure 134). 802.1W algorithm determines
that the RST BPDU that Port4/Switch 200 received is superior to what it can generate, so
Port4/Switch 200 assumes a Root port role.
FIGURE 134 New root bridge sending a proposal flag
Switch 100
Port2
Designated
port
Switch 60
Port1
Port2
Root port
Handshake
Completed
Port4
Designated port
Proposing
Proposing
Port1
Root port
Forwarding
RST BPDU
sent with
a Proposing
flag
Port4
Designated port
Proposed
Switch 200
Port2
Port3
Port2
Port3
Switch 300
Switch 400