■

■検証1：RSTPを設定して動作を確認する
　　　 ⇒各SWにRSTPを設定する

　　　 ⇒各SWのRSTPにおけるポートの役割を確認する

　　　 ⇒SW1_2950のfa0/1側のケーブルを抜線

　　　 ⇒SW3_2950のfa0/2側のケーブルを抜線

　　　 ⇒再び、各SWのRSTPにおけるポートの役割を確認する

　　　 ⇒debugを確認する

■SW1_2950投入コンフィグ
conf t
!
vlan 100
!
spanning-tree mode rapid-pvst
spanning-tree vlan 100 priority 4096
!
int fa0/1
switchport mode access
switchport access vlan 100
!
int fa0/2
switchport mode access
switchport access vlan 100
!
end

■SW2_2950投入コンフィグ
conf t
!
vlan 100
!
spanning-tree mode rapid-pvst
!
int fa0/1
switchport mode access
switchport access vlan 100
!
int fa0/2
switchport mode access
switchport access vlan 100
!
end

■SW3_2950投入コンフィグ
conf t
!
vlan 100
!
spanning-tree mode rapid-pvst
spanning-tree vlan 100 priority 8192
!
int fa0/1
switchport mode access
switchport access vlan 100
!
int fa0/2
switchport mode access
switchport access vlan 100
!
int fa0/3
switchport mode access
switchport access vlan 100
!
end

■検証1：RSTPを設定して動作を確認する
　　　 ⇒各SWのRSTPにおけるポートの役割を確認する
SW1_2950#sh spanning-tree

VLAN0100
Spanning tree enabled protocol rstp
Root ID Priority 4196
Address 000e.3854.be00
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 4196 (priority 4096 sys-id-ext 100)
Address 000e.3854.be00
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300

Interface Role Sts Cost Prio.Nbr Type

• • • • • • • • • • • • • • • • ---- --- --------- -------- --------------------------------

Fa0/1 Desg FWD 19 128.1 P2p
Fa0/2 Desg FWD 19 128.2 P2p

SW2_2950#sh spanning-tree

VLAN0100
Spanning tree enabled protocol rstp
Root ID Priority 4196
Address 000e.3854.be00
Cost 19
Port 1 (FastEthernet0/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32868 (priority 32768 sys-id-ext 100)
Address 000d.bc1d.c100
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300

Interface Role Sts Cost Prio.Nbr Type

• • • • • • • • • • • • • • • • ---- --- --------- -------- --------------------------------

Fa0/1 Root FWD 19 128.1 P2p
Fa0/2 Altn BLK 19 128.2 P2p

SW3_2950#sh spanning-tree

VLAN0100
Spanning tree enabled protocol rstp
Root ID Priority 4196
Address 000e.3854.be00
Cost 19
Port 1 (FastEthernet0/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 8292 (priority 8192 sys-id-ext 100)
Address 000d.2903.e680
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300

Interface Role Sts Cost Prio.Nbr Type

• • • • • • • • • • • • • • • • ---- --- --------- -------- --------------------------------

Fa0/1 Root FWD 19 128.1 P2p
Fa0/2 Desg FWD 19 128.2 P2p
Fa0/3 Back BLK 19 128.3 P2p

　　　 ⇒SW1_2950のfa0/1側のケーブルを抜線

　　　 ⇒SW3_2950のfa0/2側のケーブルを抜線

　　　 ⇒再び、各SWのRSTPにおけるポートの役割を確認する
SW1_2950#sh spanning-tree

VLAN0100
Spanning tree enabled protocol rstp
Root ID Priority 4196
Address 000e.3854.be00
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 4196 (priority 4096 sys-id-ext 100)
Address 000e.3854.be00
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300

Interface Role Sts Cost Prio.Nbr Type

• • • • • • • • • • • • • • • • ---- --- --------- -------- --------------------------------

Fa0/2 Desg FWD 19 128.2 P2p

SW2_2950#sh spanning-tree

VLAN0100
Spanning tree enabled protocol rstp
Root ID Priority 4196
Address 000e.3854.be00
Cost 38
Port 2 (FastEthernet0/2)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32868 (priority 32768 sys-id-ext 100)
Address 000d.bc1d.c100
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300

Interface Role Sts Cost Prio.Nbr Type

• • • • • • • • • • • • • • • • ---- --- --------- -------- --------------------------------

Fa0/2 Root FWD 19 128.2 P2p

SW3_2950#sh spanning-tree

VLAN0100
Spanning tree enabled protocol rstp
Root ID Priority 4196
Address 000e.3854.be00
Cost 19
Port 1 (FastEthernet0/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 8292 (priority 8192 sys-id-ext 100)
Address 000d.2903.e680
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300

Interface Role Sts Cost Prio.Nbr Type

• • • • • • • • • • • • • • • • ---- --- --------- -------- --------------------------------

Fa0/1 Root FWD 19 128.1 P2p
Fa0/3 Desg FWD 19 128.3 P2p

　　　 ⇒debugを確認する
SW2_2950#debug spanning-tree events
01:48:32: RSTP(100): updt roles, root port Fa0/1 is going down
01:48:32: RSTP(100): Fa0/2 is now root port
01:48:37: RSTP(100): Fa0/2 rcvd info expired
01:48:37: RSTP(100): updt roles, information on root port Fa0/2 expired
01:48:37: RSTP(100): we become the root bridge
01:48:37: RSTP(100): Fa0/2 is now designated
01:48:37: RSTP(100): updt roles, superior bpdu on Fa0/2 (synced=0)
01:48:37: RSTP(100): Fa0/2 is now root port
01:48:37: RSTP(100): synced Fa0/2
01:48:37: RSTP(100): transmitting an agreement on Fa0/2 as a response to a proposal