HP ProCurve 9304M Installation And Configuration Manual page 231

Configuring Spanning Tree Protocol (STP) and Advanced STP Features
Ports on Routing Switch 2
Port2 on Routing Switch 2 directly connects to the root bridge; therefore, Port2 is the Root port.
Routing Switch 2's bridge priority value is superior to that of Routing Switch 3 and Routing Switch 4; therefore, the
ports on Routing Switch 2 that connect to Routing Switch 3 and Routing Switch 4 are given the Designated port
role.
Furthermore, Port7 and Port8 on Routing Switch 2 are physically connected. The RST BPDUs transmitted by
Port7 are superior to those Port8 transmits. Therefore, Routing Switch 2 is the Backup port and Port7 is the
Designated port.
Ports on Routing Switch 3
Port2 on Routing Switch 3 directly connects to the Designated port on the root bridge; therefore, it assumes the
Root port role.
The root path cost of the RST BPDUs received on Port4/Routing Switch 3 is inferior to the RST BPDUs
transmitted by the port; therefore, Port4/Routing Switch 3 becomes the Designated port.
Similarly Routing Switch 3 has a bridge priority value inferior to Routing Switch 2. Port3 on Routing Switch 3
connects to Port 3 on Routing Switch 2. This port will be given the Alternate port role, since a Root port is already
established on this bridge.
Ports Routing Switch 4
Routing Switch 4 is not directly connected to the root bridge. It has two ports with superior incoming RST BPDUs
from two separate LANs: Port3 and Port4. The RST BPDUs received on Port3 are superior to the RST BPDUs
received on port 4; therefore, Port3 becomes the Root port and Port4 becomes the Alternate port.
E d g e P o r t s an d E d g e P o r t Ro l e s
HP's implementation of 802.1W allows ports that are configured as Edge ports to be present in an 802.1W
topology. (Figure 8.2). Edge ports are ports of a bridge that connect to workstations or computers. Edge ports do
not register any incoming BPDU activities.
Edge ports assume Designated port roles. Port flapping does not cause any topology change events on Edge
ports since 802.1W does not consider Edge ports in the spanning tree calculations.
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