IntermediateUnlock
STP 3: Path Cost — Choose the Forwarding Link (VLAN 30)
Engineer which trunk forwards by tuning STP path cost in a 3-switch triangle. Force SW1 as the VLAN 30 root at a deterministic priority, enable Rapid-PVST+, harden edge ports with PortFast and BPDU Guard, and raise the STP cost on SW3’s direct uplink to SW1 so SW3 prefers the longer, indirect path via SW2. Verify the resulting root port, alternate (blocked) port, and host reachability across the chosen path.