🌲
STP の練習
本エントリについて
Dynagen、Dynamips を使って、STP を練習します。
Dynagen、Dynamips の利用環境はすでに整っているものとします。
環境について
sw01 と sw02 間で、trunk ポートに設定した fa1/14、fa1/15 同士を結線して、STP の動作を確認します。
fa1/15 間の結線は後ほど実施します。
[pc0] .1 (vlan10) fa1/0 [sw01] fa1/14 === fa1/14 [sw02] fa1/0 (vlan10) .2 pc2
[pc1] .2 (vlan11) fa1/4 fa1/15 fa1/15 fa1/4 (vlan11) .2 pc3
Dynagen 設定ファイル抜粋
[[ROUTER sw02]]
model = 3725
slot1 = NM-16ESW
f1/0 = NIO_udp:30000:127.0.0.1:20000
f1/4 = NIO_udp:30002:127.0.0.1:20002
f1/14 = sw01 f1/14
[[ROUTER sw01]]
model = 3725
slot1 = NM-16ESW
f1/0 = nio_tap:tap0
f1/4 = NIO_udp:30001:127.0.0.1:20001
f1/14 = sw02 f1/14
基本設定
sw01
sw01 で VLAN10、VLAN11 を作成します。
f1/14 を trunk ポートに設定します。
sw01#show int trunk
Port Mode Encapsulation Status Native vlan
Fa1/14 on 802.1q trunking 1
Port Vlans allowed on trunk
Fa1/14 1-4094
Port Vlans allowed and active in management domain
Fa1/14 1,10-11
Port Vlans in spanning tree forwarding state and not pruned
Fa1/14 1
sw01#show int status
Port Name Status Vlan Duplex Speed Type
Fa1/0 connected 1 a-full a-100 10/100BaseTX
Fa1/1 notconnect 1 auto auto 10/100BaseTX
Fa1/2 notconnect 1 auto auto 10/100BaseTX
Fa1/3 notconnect 1 auto auto 10/100BaseTX
Fa1/4 connected 1 a-full a-100 10/100BaseTX
Fa1/5 notconnect 1 auto auto 10/100BaseTX
Fa1/6 notconnect 1 auto auto 10/100BaseTX
Fa1/7 notconnect 1 auto auto 10/100BaseTX
Fa1/8 notconnect 1 auto auto 10/100BaseTX
Fa1/9 notconnect 1 auto auto 10/100BaseTX
Fa1/10 notconnect 1 auto auto 10/100BaseTX
Fa1/11 notconnect 1 auto auto 10/100BaseTX
Fa1/12 notconnect 1 auto auto 10/100BaseTX
Fa1/13 notconnect 1 auto auto 10/100BaseTX
Fa1/14 connected trunk a-full a-100 10/100BaseTX
Fa1/15 notconnect 1 auto auto 10/100BaseTX
STPの状態を確認します。
sw01#show spanning-tree summary
Root bridge for: VLAN1, VLAN10, VLAN11.
PortFast BPDU Guard is disabled
UplinkFast is disabled
BackboneFast is disabled
Name Blocking Listening Learning Forwarding STP Active
-------------------- -------- --------- -------- ---------- ----------
VLAN1 0 0 0 3 3
VLAN10 0 0 0 1 1
VLAN11 0 0 0 1 1
-------------------- -------- --------- -------- ---------- ----------
3 VLANs 0 0 0 5 5
VLAN1、VLAN10、VLAN11 とも sw01 が root ブリッジとなっています。
sw01#show spanning-tree brief [2/568]
VLAN1
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0000
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c200.0347.0000
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/0 128.41 128 19 FWD 0 32768 c200.0347.0000 128.41
FastEthernet1/4 128.45 128 19 FWD 0 32768 c200.0347.0000 128.45
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0000 128.55
VLAN10
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0001
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c200.0347.0001
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0001 128.55
VLAN11
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0002
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c200.0347.0002
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0002 128.55
sw02
sw02 でも同様に VLAN10、VLAN11 を作成し、f1/14 を trunk ポートに設定します。
sw02#show int trunk
Port Mode Encapsulation Status Native vlan
Fa1/14 on 802.1q trunking 1
Port Vlans allowed on trunk
Fa1/14 1-4094
Port Vlans allowed and active in management domain
Fa1/14 1,10-11
Port Vlans in spanning tree forwarding state and not pruned
Fa1/14 1
sw02#
sw02#show int status
Port Name Status Vlan Duplex Speed Type
Fa1/0 connected 1 a-full a-100 10/100BaseTX
Fa1/1 notconnect 1 auto auto 10/100BaseTX
Fa1/2 notconnect 1 auto auto 10/100BaseTX
Fa1/3 notconnect 1 auto auto 10/100BaseTX
Fa1/4 connected 1 a-full a-100 10/100BaseTX
Fa1/5 notconnect 1 auto auto 10/100BaseTX
Fa1/6 notconnect 1 auto auto 10/100BaseTX
Fa1/7 notconnect 1 auto auto 10/100BaseTX
Fa1/8 notconnect 1 auto auto 10/100BaseTX
Fa1/9 notconnect 1 auto auto 10/100BaseTX
Fa1/10 notconnect 1 auto auto 10/100BaseTX
Fa1/11 notconnect 1 auto auto 10/100BaseTX
Fa1/12 notconnect 1 auto auto 10/100BaseTX
Fa1/13 notconnect 1 auto auto 10/100BaseTX
Fa1/14 connected trunk a-full a-100 10/100BaseTX
Fa1/15 notconnect 1 auto auto 10/100BaseTX
STPの状態を確認します。
sw02#show spanning-tree summary
Root bridge for: none.
PortFast BPDU Guard is disabled
UplinkFast is disabled
BackboneFast is disabled
Name Blocking Listening Learning Forwarding STP Active
-------------------- -------- --------- -------- ---------- ----------
VLAN1 0 0 0 3 3
VLAN10 0 0 0 1 1
VLAN11 0 0 0 1 1
-------------------- -------- --------- -------- ---------- ----------
3 VLANs 0 0 0 5 5
VLAN1、VLAN10、VLAN11 とも sw02 は root ブリッジではありません。
冗長回線がないので、ブロッキングになっているポートはありません。
sw02#show spanning-tree brief [4/586]
VLAN1
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0000
Cost 19
Port 55 (FastEthernet1/14)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c201.0347.0000
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/0 128.41 128 19 FWD 19 32768 c201.0347.0000 128.41
FastEthernet1/4 128.45 128 19 FWD 19 32768 c201.0347.0000 128.45
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0000 128.55
VLAN10
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0001
Cost 19
Port 55 (FastEthernet1/14)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c201.0347.0001
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0001 128.55
VLAN11
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0002
Cost 19
Port 55 (FastEthernet1/14)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c201.0347.0002
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0002 128.55
冗長回線の追加
sw01、sw02 の fa1/15 で trunk ポートの設定をします。
設定したら、dynagen で fa1/15 同士を結線します。
=> conf
=>(config)hypervisor 127.0.0.1:7200
=>(config-127.0.0.1:7200)router sw01
=>(config-127.0.0.1:7200-router sw01)f1/15 = sw02 fa1/15
結線後の状態を確認します。
sw01#show int trunk
Port Mode Encapsulation Status Native vlan
Fa1/14 on 802.1q trunking 1
Fa1/15 on 802.1q trunking 1
Port Vlans allowed on trunk
Fa1/14 1-4094
Fa1/15 1-4094
Port Vlans allowed and active in management domain
Fa1/14 1,10-11
Fa1/15 1,10-11
Port Vlans in spanning tree forwarding state and not pruned
Fa1/14 1
Fa1/15 1
sw01#show int status
Port Name Status Vlan Duplex Speed Type
Fa1/0 connected 1 a-full a-100 10/100BaseTX
Fa1/1 notconnect 1 auto auto 10/100BaseTX
Fa1/2 notconnect 1 auto auto 10/100BaseTX
Fa1/3 notconnect 1 auto auto 10/100BaseTX
Fa1/4 connected 1 a-full a-100 10/100BaseTX
Fa1/5 notconnect 1 auto auto 10/100BaseTX
Fa1/6 notconnect 1 auto auto 10/100BaseTX
Fa1/7 notconnect 1 auto auto 10/100BaseTX
Fa1/8 notconnect 1 auto auto 10/100BaseTX
Fa1/9 notconnect 1 auto auto 10/100BaseTX
Fa1/10 notconnect 1 auto auto 10/100BaseTX
Fa1/11 notconnect 1 auto auto 10/100BaseTX
Fa1/12 notconnect 1 auto auto 10/100BaseTX
Fa1/13 notconnect 1 auto auto 10/100BaseTX
Fa1/14 connected trunk a-full a-100 10/100BaseTX
Fa1/15 connected trunk a-full a-100 10/100BaseTX
STPの状態を確認します。
sw01#show spanning-tree summary
Root bridge for: VLAN1, VLAN10, VLAN11.
PortFast BPDU Guard is disabled
UplinkFast is disabled
BackboneFast is disabled
Name Blocking Listening Learning Forwarding STP Active
-------------------- -------- --------- -------- ---------- ----------
VLAN1 0 0 0 4 4
VLAN10 0 0 0 2 2
VLAN11 0 0 0 2 2
-------------------- -------- --------- -------- ---------- ----------
3 VLANs 0 0 0 8 8
sw01#show spanning-tree brief
VLAN1
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0000
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c200.0347.0000
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/0 128.41 128 19 FWD 0 32768 c200.0347.0000 128.41
FastEthernet1/4 128.45 128 19 FWD 0 32768 c200.0347.0000 128.45
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0000 128.55
FastEthernet1/15 128.56 128 19 FWD 0 32768 c200.0347.0000 128.56
VLAN10
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0001
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c200.0347.0001
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0001 128.55
FastEthernet1/15 128.56 128 19 FWD 0 32768 c200.0347.0001 128.56
VLAN11
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0002
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c200.0347.0002
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0002 128.55
FastEthernet1/15 128.56 128 19 FWD 0 32768 c200.0347.0002 128.56
sw02でも同様に確認します。
sw02#show int trunk
Port Mode Encapsulation Status Native vlan
Fa1/14 on 802.1q trunking 1
Fa1/15 on 802.1q trunking 1
Port Vlans allowed on trunk
Fa1/14 1-4094
Fa1/15 1-4094
Port Vlans allowed and active in management domain
Fa1/14 1,10-11
Fa1/15 1,10-11
Port Vlans in spanning tree forwarding state and not pruned
Fa1/14 1
Fa1/15 none
sw02#show int status
Port Name Status Vlan Duplex Speed Type
Fa1/0 connected 1 a-full a-100 10/100BaseTX
Fa1/1 notconnect 1 auto auto 10/100BaseTX
Fa1/2 notconnect 1 auto auto 10/100BaseTX
Fa1/3 notconnect 1 auto auto 10/100BaseTX
Fa1/4 connected 1 a-full a-100 10/100BaseTX
Fa1/5 notconnect 1 auto auto 10/100BaseTX
Fa1/6 notconnect 1 auto auto 10/100BaseTX
Fa1/7 notconnect 1 auto auto 10/100BaseTX
Fa1/8 notconnect 1 auto auto 10/100BaseTX
Fa1/9 notconnect 1 auto auto 10/100BaseTX
Fa1/10 notconnect 1 auto auto 10/100BaseTX
Fa1/11 notconnect 1 auto auto 10/100BaseTX
Fa1/12 notconnect 1 auto auto 10/100BaseTX
Fa1/13 notconnect 1 auto auto 10/100BaseTX
Fa1/14 connected trunk a-full a-100 10/100BaseTX
Fa1/15 connected trunk a-full a-100 10/100BaseTX
STPの状態を確認します。
sw02#show spanning-tree summary
Root bridge for: none.
PortFast BPDU Guard is disabled
UplinkFast is disabled
BackboneFast is disabled
Name Blocking Listening Learning Forwarding STP Active
-------------------- -------- --------- -------- ---------- ----------
VLAN1 1 0 0 3 4
VLAN10 1 0 0 1 2
VLAN11 1 0 0 1 2
-------------------- -------- --------- -------- ---------- ----------
3 VLANs 3 0 0 5 8
3つのVLANとも fa1/15 がブロッキングポートとなっています。
sw02#show spanning-tree brief
VLAN1
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0000
Cost 19
Port 55 (FastEthernet1/14)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c201.0347.0000
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/0 128.41 128 19 FWD 19 32768 c201.0347.0000 128.41
FastEthernet1/4 128.45 128 19 FWD 19 32768 c201.0347.0000 128.45
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0000 128.55
FastEthernet1/15 128.56 128 19 BLK 0 32768 c200.0347.0000 128.56
VLAN10
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0001
Cost 19
Port 55 (FastEthernet1/14)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c201.0347.0001
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0001 128.55
FastEthernet1/15 128.56 128 19 BLK 0 32768 c200.0347.0001 128.56
VLAN11
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0002
Cost 19
Port 55 (FastEthernet1/14)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c201.0347.0002
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0002 128.55
FastEthernet1/15 128.56 128 19 BLK 0 32768 c200.0347.0002 128.56
ブリッジのプライオリティを変更する。
ルートブリッジの選出においてはブリッジIDを比較して、値の小さいスイッチがルートブリッジに選出されます。
ブリッジIDは、ブリッジプライオリティ + MACアドレスで表されます。
ブリッジプライオリティを変更することで、ルートブリッジの選出に影響を与えることができます。
sw02
sw02 で vlan11 の ブリッジプライオリティを変更してみます。
sw02(config)#spanning-tree vlan 11 root primary
状態を確認します。
sw02#show spanning-tree summary
Root bridge for: VLAN11.
PortFast BPDU Guard is disabled
UplinkFast is disabled
BackboneFast is disabled
Name Blocking Listening Learning Forwarding STP Active
-------------------- -------- --------- -------- ---------- ----------
VLAN1 1 0 0 3 4
VLAN10 1 0 0 1 2
VLAN11 0 0 0 2 2
-------------------- -------- --------- -------- ---------- ----------
3 VLANs 2 0 0 6 8
VLAN11のみ、こちらがルートブリッジになりました。
VLAN1、VLAN10 の fa1/15 がブロッキングとなっています。
sw02#show spanning-tree brief
VLAN1
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0000
Cost 19
Port 55 (FastEthernet1/14)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c201.0347.0000
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/0 128.41 128 19 FWD 19 32768 c201.0347.0000 128.41
FastEthernet1/4 128.45 128 19 FWD 19 32768 c201.0347.0000 128.45
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0000 128.55
FastEthernet1/15 128.56 128 19 BLK 0 32768 c200.0347.0000 128.56
VLAN10
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0001
Cost 19
Port 55 (FastEthernet1/14)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c201.0347.0001
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0001 128.55
FastEthernet1/15 128.56 128 19 BLK 0 32768 c200.0347.0001 128.56
VLAN11
Spanning tree enabled protocol ieee
Root ID Priority 8192
Address c201.0347.0002
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 8192
Address c201.0347.0002
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 128.55 128 19 FWD 0 8192 c201.0347.0002 128.55
FastEthernet1/15 128.56 128 19 FWD 0 8192 c201.0347.0002 128.56
sw01 でも確認します。
sw01#show spanning-tree summary
Root bridge for: VLAN1, VLAN10.
PortFast BPDU Guard is disabled
UplinkFast is disabled
BackboneFast is disabled
Name Blocking Listening Learning Forwarding STP Active
-------------------- -------- --------- -------- ---------- ----------
VLAN1 0 0 0 4 4
VLAN10 0 0 0 2 2
VLAN11 1 0 0 1 2
-------------------- -------- --------- -------- ---------- ----------
3 VLANs 1 0 0 7 8
VLAN1、VLAN10とも、引き続きこちらがルートブリッジです。
VLAN11 の fa1/15 がブロッキングとなっています。
sw01#show spanning-tree brief
VLAN1
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0000
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c200.0347.0000
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/0 128.41 128 19 FWD 0 32768 c200.0347.0000 128.41
FastEthernet1/4 128.45 128 19 FWD 0 32768 c200.0347.0000 128.45
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0000 128.55
FastEthernet1/15 128.56 128 19 FWD 0 32768 c200.0347.0000 128.56
VLAN10
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0001
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c200.0347.0001
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0001 128.55
FastEthernet1/15 128.56 128 19 FWD 0 32768 c200.0347.0001 128.56
VLAN11
Spanning tree enabled protocol ieee
Root ID Priority 8192
Address c201.0347.0002
Cost 19
Port 55 (FastEthernet1/14)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c200.0347.0002
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 128.55 128 19 FWD 0 8192 c201.0347.0002 128.55
FastEthernet1/15 128.56 128 19 BLK 0 8192 c201.0347.0002 128.56
ルートブリッジが変わっただけでは、ポートの負荷分散の役にはたちません。
確認したら設定を戻します。
sw02#conf t
sw02(config)#no spanning-tree vlan 11 root primary
ポートコストの変更
ルートポートの選出においては、送信されてくるBPDUのルートパスコスト、送信元ブリッジID、送信元ポートID の順で比較し、小さい値のポートがルートポートになります。
ポートコストを変更することで、ルートポートの選出に影響を与えることができます。
sw02
sw02 で vlan11 の fa1/14 のポートコストを悪化させます。
sw02(config)#int fa1/14
sw02(config-if)#spanning-tree vlan 11 cost 20
状態を確認します。
VLAN11の fa1/14 が ブロッキングに、fa1/15 がフォワーディングに変化しました。
sw02#show spanning-tree brief [8/1510]
VLAN1
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0000
Cost 19
Port 55 (FastEthernet1/14)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c201.0347.0000
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/0 128.41 128 19 FWD 19 32768 c201.0347.0000 128.41
FastEthernet1/4 128.45 128 19 FWD 19 32768 c201.0347.0000 128.45
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0000 128.55
FastEthernet1/15 128.56 128 19 BLK 0 32768 c200.0347.0000 128.56
VLAN10
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0001
Cost 19
Port 55 (FastEthernet1/14)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c201.0347.0001
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0001 128.55
FastEthernet1/15 128.56 128 19 BLK 0 32768 c200.0347.0001 128.56
VLAN11
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0002
Cost 19
Port 56 (FastEthernet1/15)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c201.0347.0002
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 128.55 128 20 BLK 0 32768 c200.0347.0002 128.55
FastEthernet1/15 128.56 128 19 FWD 0 32768 c200.0347.0002 128.56
sw01
sw01 でも確認します。
こちらではポートの役割の変更はありません。
sw01#show spanning-tree brief
VLAN1
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0000
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c200.0347.0000
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/0 128.41 128 19 FWD 0 32768 c200.0347.0000 128.41
FastEthernet1/4 128.45 128 19 FWD 0 32768 c200.0347.0000 128.45
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0000 128.55
FastEthernet1/15 128.56 128 19 FWD 0 32768 c200.0347.0000 128.56
VLAN10
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0001
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c200.0347.0001
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0001 128.55
FastEthernet1/15 128.56 128 19 FWD 0 32768 c200.0347.0001 128.56
VLAN11
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0002
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c200.0347.0002
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0002 128.55
FastEthernet1/15 128.56 128 19 FWD 0 32768 c200.0347.0002 128.56
設定を元に戻します。
sw02(config)#int fa1/14
sw02(config-if)#no spanning-tree vlan 11 cost 20
ポートプライオリティの変更
送信元ポートIDは、ポートプライオリティ + ポート番号で表されます。
ポートプライオリティを変更することによっても、ルートポートの選出に影響を与えることができます。
sw01
sw01 で vlan11 の fa1/14 のポートプライオリティを変更して、優先度を下げてみます。
sw01(config-if)#int fa1/14
sw01(config-if)#spanning-tree vlan 11 port-priority 144
状態を確認します。
こちらではポートの役割の変更はありません。
sw01#show spanning-tree brief
VLAN1
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0000
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c200.0347.0000
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/0 128.41 128 19 FWD 0 32768 c200.0347.0000 128.41
FastEthernet1/4 128.45 128 19 FWD 0 32768 c200.0347.0000 128.45
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0000 128.55
FastEthernet1/15 128.56 128 19 FWD 0 32768 c200.0347.0000 128.56
VLAN10
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0001
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c200.0347.0001
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0001 128.55
FastEthernet1/15 128.56 128 19 FWD 0 32768 c200.0347.0001 128.56
VLAN11
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0002
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c200.0347.0002
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 144.55 144 19 FWD 0 32768 c200.0347.0002 144.55
FastEthernet1/15 128.56 128 19 FWD 0 32768 c200.0347.0002 128.56
sw02 でも確認します。
この場合でも、VLAN11の fa1/14 が ブロッキングに、fa1/15 がフォワーディングに変化しました。
sw02#show spanning-tree brief
VLAN1
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0000
Cost 19
Port 55 (FastEthernet1/14)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c201.0347.0000
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/0 128.41 128 19 FWD 19 32768 c201.0347.0000 128.41
FastEthernet1/4 128.45 128 19 FWD 19 32768 c201.0347.0000 128.45
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0000 128.55
FastEthernet1/15 128.56 128 19 BLK 0 32768 c200.0347.0000 128.56
VLAN10
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0001
Cost 19
Port 55 (FastEthernet1/14)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c201.0347.0001
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 128.55 128 19 FWD 0 32768 c200.0347.0001 128.55
FastEthernet1/15 128.56 128 19 BLK 0 32768 c200.0347.0001 128.56
VLAN11
Spanning tree enabled protocol ieee
Root ID Priority 32768
Address c200.0347.0002
Cost 19
Port 56 (FastEthernet1/15)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c201.0347.0002
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Designated
Name Port ID Prio Cost Sts Cost Bridge ID Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/14 128.55 128 19 BLK 0 32768 c200.0347.0002 144.55
FastEthernet1/15 128.56 128 19 FWD 0 32768 c200.0347.0002 128.56
確認したら設定を戻します。
sw01(config-if)#int fa1/14
sw01(config-if)#no spanning-tree vlan 11 port-priority 144
コンバージェンス高速化技術
portfast
即時収束される。引き続きBPDUは送信される。
ブリッジが接続されないポート(PC等の端末が接続されるポート)で設定
(config-if)# spanning-tree portfast
uplinkfast
ルートポートにリンク障害があったときに、ルートポートの役割を5秒以内に非指定ポートに引き継がせる。
root, secondary root ではないスイッチで設定
(config)# spanning-tree uplinkfast
backbonefast
間接リンクに障害があったときのコンバージェンス時間(50秒:20⁺20⁺15)を20秒短縮する。
最大エージ待たずに、非指定ポートをリスニング状態へ移行。
全てのスイッチで設定
(config)# spanning-tree backbonefast
まとめ
Dynagen、Dynamips を使って、STP の、ルートブリッジ、ルートポートの変更を練習しました。
STPでは、自分でルートブリッジや、ルートポート、あるいは非指定ポートをコントロールできます。
dynamips で対応しているのは 基本的な STP のみで、RSTP等には対応していません。これらの検証には他の手段が必要となってきます。
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