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To get SW2 to use Gi1/1 as the root port, you can decrease the port cost from 4 to 2:

SW2(config)#int gigabitEthernet 1/1 SW2(config-if)#spanning-tree vlan 1 cost ? <1-200000000> Change an interface's per VLAN spanning tree path cost SW2(config-if)#spanning-tree vlan 1 cost 2 SW2(config-if)#do show spanning-tree vlan 1 VLAN0001 Spanning tree enabled protocol rstp Root ID Priority 32769 Address 0015.fa83.e900 Cost 6 Port 6 (GigabitEthernet1/1) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 32769 (priority 32768 sys-id-ext 1) Address 0015.fa88.4e80 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300 sec Interface Role Sts Cost Prio.Nbr Type ------------------- ---- --- --------- -------- -------------------------------- Gi0/0 Altn BLK 4 128.1 P2p Gi0/1 Altn BLK 4 128.2 P2p Gi0/2 Desg BLK 4 128.3 P2p Gi0/3 Desg BLK 4 128.4 P2p Gi1/0 Altn BLK 4 128.5 P2p Gi1/1 Root FWD 2 128.6 P2p ! Output truncated

Gi1/1 is now the root port. Let's change it back to 4:

SW2(config-if)#spanning-tree vlan 1 cost 4 SW2(config-if)#do show spanning-tree vlan 1 VLAN0001 Spanning tree enabled protocol rstp Root ID Priority 32769 Address 0015.fa83.e900 Cost 8 Port 5 (GigabitEthernet1/0) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 32769 (priority 32768 sys-id-ext 1) Address 0015.fa88.4e80 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300 sec Interface Role Sts Cost Prio.Nbr Type ------------------- ---- --- --------- -------- -------------------------------- Gi0/0 Altn BLK 4 128.1 P2p Gi0/1 Altn BLK 4 128.2 P2p Gi0/2 Desg BLK 4 128.3 P2p Gi0/3 Desg BLK 4 128.4 P2p Gi1/0 Root FWD 4 128.5 P2p Gi1/1 Altn BLK 4 128.6 P2p ! Output truncated

Gi1/0 is once again the root port.