GNS3 活用 - Cisco スイッチ STP 編 その7 （backbonefast で障害検知と対応）
backbonefast をやってみました。
お疲れさまです。ニックネーム たいちょう です。
今回は、backbonefastをやってみたいです。前回（GNS3 活用 - Cisco スイッチ STP 編 その6 （uplinkfast で障害に強いネットワークを））の続きです。
結論的には、設定はできたのですが、動きませんでした。
とりあえず、結果を張っておきます。
トポロジは、簡単な三角形+1のものにしました。
debug spanning-tree events を実行しておく。
Sw1#sh spanning-tree bri
VLAN1
Spanning tree enabled protocol ieee
Root ID Priority 8192
Address c402.60c2.0000
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 8192
Address c402.60c2.0000
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
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/1 128.42 128 19 FWD 0 8192 c402.60c2.0000 128.42
FastEthernet1/3 128.44 128 19 FWD 0 8192 c402.60c2.0000 128.44
Sw1#
*Mar 1 00:20:28.843: STP: VLAN1 Fa1/1 -> forwarding
Sw2#sh spanning-tree bri
VLAN1
Spanning tree enabled protocol ieee
Root ID Priority 8192
Address c402.60c2.0000
Cost 19
Port 42 (FastEthernet1/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 16384
Address c403.60d0.0000
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
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/1 128.42 128 19 FWD 0 8192 c402.60c2.0000 128.42
FastEthernet1/14 128.55 128 19 FWD 19 16384 c403.60d0.0000 128.55
Sw3#sh spanning-tree bri
VLAN1
Spanning tree enabled protocol ieee
Root ID Priority 8192
Address c402.60c2.0000
Cost 19
Port 44 (FastEthernet1/3)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c404.60df.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
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/3 128.44 128 19 FWD 0 8192 c402.60c2.0000 128.44
FastEthernet1/15 128.56 128 19 FWD 19 32768 c404.60df.0000 128.56
Sw4#sh spanning-tree bri
VLAN1
Spanning tree enabled protocol ieee
Root ID Priority 8192
Address c402.60c2.0000
Cost 38
Port 55 (FastEthernet1/14)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32768
Address c406.2668.0000
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 38 32768 c406.2668.0000 128.41
FastEthernet1/1 128.42 128 19 FWD 38 32768 c406.2668.0000 128.42
FastEthernet1/14 128.55 128 19 FWD 19 16384 c403.60d0.0000 128.55
FastEthernet1/15 128.56 128 19 BLK 19 32768 c404.60df.0000 128.56
この状態で、Sw1のfa1/1とfa1/3をシャットダウンする。
Sw1(config)#int fa1/1
Sw1(config-if)#shut
Sw1(config-if)#int
*Mar 1 01:02:11.395: STP: VLAN1 Fa1/1 -> blocking
Sw1(config-if)#int fa1/3
*Mar 1 01:02:13.379: %LINK-5-CHANGED: Interface FastEthernet1/1, changed state to administratively down
*Mar 1 01:02:14.379: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet1/1, changed state to down
Sw1(config-if)#int fa1/3
Sw1(config-if)#shut
Sw1(config-if)#
*Mar 1 01:02:17.323: STP: VLAN1 Fa1/3 -> blocking
Sw1(config-if)#
*Mar 1 01:02:18.319: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down
*Mar 1 01:02:19.319: %LINK-5-CHANGED: Interface FastEthernet1/3, changed state to administratively down
Sw1(config-if)#
*Mar 1 01:02:20.319: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet1/3, changed state to down
Sw2#
*Mar 1 01:02:30.163: STP: VLAN1 we are the spanning tree root
*Mar 1 01:02:30.191: STP: VLAN1 heard root 8192-c402.60c2.0000 on Fa1/14
*Mar 1 01:02:30.191: current Root has 16384-c403.60d0.0000
*Mar 1 01:02:30.191: supersedes 16384-c403.60d0.0000
*Mar 1 01:02:30.191: STP: VLAN1 new root is 8192, c402.60c2.0000 on port Fa1/14, cost 57
*Mar 1 01:02:30.191: STP: VLAN1 sent Topology Change Notice on Fa1/14
Sw2#
*Mar 1 01:02:35.183: STP: VLAN1 we are the spanning tree root
Sw2#
*Mar 1 01:02:36.207: STP: VLAN1 heard root 32768-c406.2668.0000 on Fa1/14
*Mar 1 01:02:36.207: current Root has 16384-c403.60d0.0000
*Mar 1 01:02:36.215: STP: VLAN1 Topology Change rcvd on Fa1/14
Sw2#
*Mar 1 01:02:59.171: STP: VLAN1 Topology Change rcvd on Fa1/14
Sw3#
*Mar 1 01:02:30.199: STP: VLAN1 Topology Change rcvd on Fa1/15
*Mar 1 01:02:30.199: STP: VLAN1 sent Topology Change Notice on Fa1/3
Sw3#
*Mar 1 01:02:32.199: STP: VLAN1 sent Topology Change Notice on Fa1/3
Sw3#
*Mar 1 01:02:34.199: STP: VLAN1 sent Topology Change Notice on Fa1/3
Sw3#
*Mar 1 01:02:35.239: STP: VLAN1 heard root 32768-c406.2668.0000 on Fa1/15
*Mar 1 01:02:35.239: current Root has 8192-c402.60c2.0000
*Mar 1 01:02:36.159: STP: VLAN1 we are the spanning tree root
Sw3#
*Mar 1 01:02:36.247: STP: VLAN1 heard root 16384-c403.60d0.0000 on Fa1/15
*Mar 1 01:02:36.247: current Root has 32768-c404.60df.0000
*Mar 1 01:02:36.247: supersedes 32768-c404.60df.0000
*Mar 1 01:02:36.247: STP: VLAN1 new root is 16384, c403.60d0.0000 on port Fa1/15, cost 38
*Mar 1 01:02:36.247: STP: VLAN1 sent Topology Change Notice on Fa1/15
Sw4#
*Mar 1 01:02:29.179: STP: VLAN1 new root port Fa1/15, cost 38
*Mar 1 01:02:29.179: STP: VLAN1 Fa1/15 -> listening
Sw4#
*Mar 1 01:02:30.191: STP: VLAN1 heard root 16384-c403.60d0.0000 on Fa1/14
*Mar 1 01:02:30.191: current Root has 8192-c402.60c2.0000
*Mar 1 01:02:30.199: STP: VLAN1 Topology Change rcvd on Fa1/14
*Mar 1 01:02:30.199: STP: VLAN1 sent Topology Change Notice on Fa1/15
Sw4#
*Mar 1 01:02:35.211: STP: VLAN1 heard root 16384-c403.60d0.0000 on Fa1/14
*Mar 1 01:02:35.211: current Root has 8192-c402.60c2.0000
*Mar 1 01:02:35.223: STP: VLAN1 we are the spanning tree root
Sw4#
*Mar 1 01:02:36.223: STP: VLAN1 heard root 16384-c403.60d0.0000 on Fa1/14
*Mar 1 01:02:36.223: current Root has 32768-c406.2668.0000
*Mar 1 01:02:36.223: supersedes 32768-c406.2668.0000
*Mar 1 01:02:36.223: STP: VLAN1 new root is 16384, c403.60d0.0000 on port Fa1/14, cost 19
*Mar 1 01:02:36.223: STP: VLAN1 sent Topology Change Notice on Fa1/14
*Mar 1 01:02:36.247: STP: VLAN1 heard root 32768-c404.60df.0000 on Fa1/15
*Mar 1 01:02:36.247: current Root has 16384-c403.60d0.0000
*Mar 1 01:02:36.259: STP: VLAN1 Topology Change rcvd on Fa1/15
Sw4#
*Mar 1 01:02:44.179: STP: VLAN1 Fa1/15 -> learning
Sw4#
*Mar 1 01:02:59.179: STP: VLAN1 sent Topology Change Notice on Fa1/14
*Mar 1 01:02:59.179: STP: VLAN1 Fa1/15 -> forwarding
*Mar 1 01:02:36.223: STP: VLAN1 new root is 16384, c403.60d0.0000 on port Fa1/14, cost 19
15秒で、VLAN1 new root is 16384, c403.60d0.0000 on port Fa1/14 になった。
では、backbonefast を有効にした時はどうか。
Sw1(config)#int fa1/1
Sw1(config-if)#shut
Sw1(config-if)#int fa1/3
Sw1(config-if)#shut
Sw1(config-if)#
*Mar 1 00:53:29.883: STP: VLAN1 Fa1/3 -> blocking
Sw1(config-if)#
*Mar 1 00:53:30.867: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down
*Mar 1 00:53:31.867: %LINK-5-CHANGED: Interface FastEthernet1/3, changed state to administratively down
Sw1(config-if)#
*Mar 1 00:53:32.867: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet1/3, changed state to down
Sw2#
*Mar 1 00:53:46.539: STP: VLAN1 we are the spanning tree root
Sw2#
*Mar 1 00:53:47.559: STP: VLAN1 heard root 32768-c406.2668.0000 on Fa1/14
*Mar 1 00:53:47.559: current Root has 16384-c403.60d0.0000
*Mar 1 00:53:47.571: STP: VLAN1 Topology Change rcvd on Fa1/14
Sw3#
*Mar 1 00:53:47.531: STP: VLAN1 heard root 32768-c406.2668.0000 on Fa1/15
*Mar 1 00:53:47.531: current Root has 8192-c402.60c2.0000
*Mar 1 00:53:48.507: STP: VLAN1 we are the spanning tree root
Sw3#
*Mar 1 00:53:48.531: STP: VLAN1 heard root 16384-c403.60d0.0000 on Fa1/15
*Mar 1 00:53:48.531: current Root has 32768-c404.60df.0000
*Mar 1 00:53:48.531: supersedes 32768-c404.60df.0000
*Mar 1 00:53:48.531: STP: VLAN1 new root is 16384, c403.60d0.0000 on port Fa1/15, cost 38
*Mar 1 00:53:48.531: STP: VLAN1 sent Topology Change Notice on Fa1/15
Sw4#
*Mar 1 00:53:46.567: STP: VLAN1 heard root 16384-c403.60d0.0000 on Fa1/14
*Mar 1 00:53:46.567: current Root has 8192-c402.60c2.0000
*Mar 1 00:53:47.519: STP: VLAN1 we are the spanning tree root
Sw4#
*Mar 1 00:53:47.575: STP: VLAN1 heard root 16384-c403.60d0.0000 on Fa1/14
*Mar 1 00:53:47.575: current Root has 32768-c406.2668.0000
*Mar 1 00:53:47.575: supersedes 32768-c406.2668.0000
*Mar 1 00:53:47.575: STP: VLAN1 new root is 16384, c403.60d0.0000 on port Fa1/14, cost 19
*Mar 1 00:53:47.575: STP: VLAN1 sent Topology Change Notice on Fa1/14
*Mar 1 00:53:48.543: STP: VLAN1 heard root 32768-c404.60df.0000 on Fa1/15
*Mar 1 00:53:48.543: current Root has 16384-c403.60d0.0000
*Mar 1 00:53:48.555: STP: VLAN1 Topology Change rcvd on Fa1/15
Sw4 では、15秒で BRIDGE ROOT が VLAN1 new root is 16384, c403.60d0.0000 on port Fa1/15 となった。
あれ、変わらないじゃん。
received inferior BPDU on ... という表示が出るのを期待しているんだけど。
debug spanning-tree backbonefast ならどうだろう。
何も出てきませんでした。以下のコマンドでも、応答ありません。
Sw4#sh spanning-tree backbonefast
BackboneFast is enabled
BackboneFast statistics
-----------------------
Number of transition via backboneFast (all VLANs) : 0
Number of inferior BPDUs received (all VLANs) : 0
Number of RLQ request PDUs received (all VLANs) : 0
Number of RLQ response PDUs received (all VLANs) : 0
Number of RLQ request PDUs sent (all VLANs) : 0
Number of RLQ response PDUs sent (all VLANs) : 0
これは bug かもしれませんね。
backbonefast の実習は、Ciscoの実機を使うしかないのかもしれませんね。
お疲れさまです。次回は、pvstp をやってみようと思います。
ニックネーム たいちょう でした。次回をお楽しみに。
