Q&A###実現したいこと
・Fa1/1 - 2 or Fa1/3 - 4が死んでもPVST+の機能が働いてトポロジが切り替わりvlan10,20は継続して通信できること。
###環境
GNS3
###構成図
###ステータス
◆L3SW
L3SW#show run Building configuration... Current configuration : 2353 bytes ! version 12.4 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname L3SW ! boot-start-marker boot-end-marker ! ! no aaa new-model memory-size iomem 5 no ip icmp rate-limit unreachable ip cef ! ! no ip domain lookup ip auth-proxy max-nodata-conns 3 ip admission max-nodata-conns 3 ! ! spanning-tree vlan 10 priority 0 spanning-tree vlan 20 priority 4096 ! ! ip tcp synwait-time 5 ! ! interface Port-channel1 switchport trunk allowed vlan 1,2,10,20,1002-1005 switchport mode trunk ! interface Port-channel2 switchport trunk allowed vlan 1,2,10,20,1002-1005 switchport mode trunk ! interface FastEthernet0/0 no ip address shutdown duplex auto speed auto ! interface Serial0/0 no ip address shutdown clock rate 2000000 ! interface FastEthernet0/1 no ip address shutdown duplex auto speed auto ! interface Serial0/1 no ip address shutdown clock rate 2000000 ! interface Serial0/2 no ip address shutdown clock rate 2000000 ! interface FastEthernet1/0 ! interface FastEthernet1/1 switchport trunk allowed vlan 1,2,10,20,1002-1005 switchport mode trunk channel-group 1 mode on ! interface FastEthernet1/2 switchport trunk allowed vlan 1,2,10,20,1002-1005 switchport mode trunk channel-group 1 mode on ! interface FastEthernet1/3 switchport trunk allowed vlan 1,2,10,20,1002-1005 switchport mode trunk channel-group 2 mode on ! interface FastEthernet1/4 switchport trunk allowed vlan 1,2,10,20,1002-1005 switchport mode trunk channel-group 2 mode on ! interface FastEthernet1/5 ! interface FastEthernet1/6 ! interface FastEthernet1/7 ! interface FastEthernet1/8 ! interface FastEthernet1/9 ! interface FastEthernet1/10 ! interface FastEthernet1/11 ! interface FastEthernet1/12 ! interface FastEthernet1/13 ! interface FastEthernet1/14 ! interface FastEthernet1/15 ! interface Vlan1 no ip address ! interface Vlan10 ip address 192.168.1.254 255.255.255.0 ! interface Vlan20 ip address 192.168.2.254 255.255.255.0 ! ip forward-protocol nd ! ! no ip http server no ip http secure-server ! no cdp log mismatch duplex ! ! ! control-plane ! ! line con 0 exec-timeout 0 0 privilege level 15 logging synchronous line aux 0 exec-timeout 0 0 privilege level 15 logging synchronous line vty 0 4 login ! ! end
L3SW#show etherchannel summary Group Port-channel Ports -----+------------+----------------------------------------------------------- 1 Po1(SU) Fa1/1(P) Fa1/2(P) 2 Po2(SU) Fa1/3(P) Fa1/4(P)
L3SW#show spanning-tree brief VLAN10 Spanning tree enabled protocol ieee Root ID Priority 0 Address c401.4478.0001 This bridge is the root Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 0 Address c401.4478.0001 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 -------------------- ------- ---- ----- --- ----- -------------------- ------- Port-channel1 129.65 128 12 FWD 0 0 c401.4478.0001 129.65 Port-channel2 129.66 128 12 FWD 0 0 c401.4478.0001 129.66 VLAN20 Spanning tree enabled protocol ieee Root ID Priority 0 Address c402.1ef0.0002 Cost 12 Port 321 (Port-channel1) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 4096 Address c401.4478.0002 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 -------------------- ------- ---- ----- --- ----- -------------------- ------- Port-channel1 129.65 128 12 FWD 0 0 c402.1ef0.0002 129.65 Port-channel2 129.66 128 12 BLK 0 0 c402.1ef0.0002 129.66
◆L2SW
L2SW#show run Building configuration... Current configuration : 2383 bytes ! version 12.4 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname L2SW ! boot-start-marker boot-end-marker ! ! no aaa new-model memory-size iomem 5 no ip icmp rate-limit unreachable ip cef ! ! no ip domain lookup ip auth-proxy max-nodata-conns 3 ip admission max-nodata-conns 3 ! ! ! spanning-tree vlan 10 priority 4096 spanning-tree vlan 20 priority 0 ! ! ip tcp synwait-time 5 ! ! interface Port-channel1 switchport trunk allowed vlan 1,2,10,20,1002-1005 switchport mode trunk ! interface Port-channel2 switchport trunk allowed vlan 1,2,10,20,1002-1005 switchport mode trunk ! interface FastEthernet0/0 no ip address shutdown duplex auto speed auto ! interface Serial0/0 no ip address shutdown clock rate 2000000 ! interface FastEthernet0/1 no ip address shutdown duplex auto speed auto ! interface Serial0/1 no ip address shutdown clock rate 2000000 ! interface Serial0/2 no ip address shutdown clock rate 2000000 ! interface FastEthernet1/0 ! interface FastEthernet1/1 switchport trunk allowed vlan 1,2,10,20,1002-1005 switchport mode trunk channel-group 1 mode on ! interface FastEthernet1/2 switchport trunk allowed vlan 1,2,10,20,1002-1005 switchport mode trunk channel-group 1 mode on ! interface FastEthernet1/3 switchport trunk allowed vlan 1,2,10,20,1002-1005 switchport mode trunk channel-group 2 mode on ! interface FastEthernet1/4 switchport trunk allowed vlan 1,2,10,20,1002-1005 switchport mode trunk channel-group 2 mode on ! interface FastEthernet1/5 switchport access vlan 10 ! interface FastEthernet1/6 switchport access vlan 20 ! interface FastEthernet1/7 ! interface FastEthernet1/8 ! interface FastEthernet1/9 ! interface FastEthernet1/10 ! interface FastEthernet1/11 ! interface FastEthernet1/12 ! interface FastEthernet1/13 ! interface FastEthernet1/14 ! interface FastEthernet1/15 ! interface Vlan1 no ip address ! ip forward-protocol nd ! ! no ip http server no ip http secure-server ! no cdp log mismatch duplex ! ! ! control-plane ! ! line con 0 exec-timeout 0 0 privilege level 15 logging synchronous line aux 0 exec-timeout 0 0 privilege level 15 logging synchronous line vty 0 4 login ! ! end
L2SW#show etherchannel summary Group Port-channel Ports -----+------------+----------------------------------------------------------- 1 Po1(SU) Fa1/1(P) Fa1/2(P) 2 Po2(SU) Fa1/3(P) Fa1/4(P)
L2SW#show spanning-tree brief VLAN10 Spanning tree enabled protocol ieee Root ID Priority 0 Address c401.4478.0001 Cost 12 Port 321 (Port-channel1) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 4096 Address c402.1ef0.0001 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 -------------------- ------- ---- ----- --- ----- -------------------- ------- FastEthernet1/5 128.46 128 19 FWD 12 4096 c402.1ef0.0001 128.46 FastEthernet1/6 128.47 128 19 FWD 12 4096 c402.1ef0.0001 128.47 Port-channel1 129.65 128 12 FWD 0 0 c401.4478.0001 129.65 Port-channel2 129.66 128 12 BLK 0 0 c401.4478.0001 129.66 VLAN20 Spanning tree enabled protocol ieee Root ID Priority 0 Address c402.1ef0.0002 This bridge is the root Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 0 Address c402.1ef0.0002 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 -------------------- ------- ---- ----- --- ----- -------------------- ------- FastEthernet1/5 128.46 128 19 FWD 0 0 c402.1ef0.0002 128.46 FastEthernet1/6 128.47 128 19 FWD 0 0 c402.1ef0.0002 128.47 Port-channel1 129.65 128 12 FWD 0 0 c402.1ef0.0002 129.65 Port-channel2 129.66 128 12 FWD 0 0 c402.1ef0.0002 129.66
###現状
PC間の疎通可。
L2SWのfa1/3をshutすると通信できなくなる。
(なぜかshow spanning-tree briefの結果が全てFWDと表示される)
現在、
vlan10,20どちらもFa1/1-2のpo1で通信しており、Fa1/3-4は通信されておりません。
vlan20のNDPをFa1/1 -2にできればいいのですが、ポートIDは物理IFの番号が大きい方がポートIDの値も大きくなるため、方法が分からない状態です。
そもそも、上記の構成になったとしてもIFを閉塞した場合切り替わらなければ意味がないので、構成自体に問題があるような気がしてます。
以上、アドバイスよろしくお願いいたします(>_<)
###追記
L3SW、L2SWどちらもvlan10のプライオリティを0、vlan20のプライオリティを4096に変更し、NDPをL2SWのFa1/3-4にして切り替わり試験を試しましたが全てのIFがFWDと表示され通信不可状態でした。
回答1件
0
自己解決
自分なりに試行錯誤した結果、最初の構成では、実質片方にNDPが選出されるため、vlanごとにプライオリティ値を変更しても意味がないという結論に至り、L3SW、L2SWどちらもvlan10のプライオリティを0、vlan20のプライオリティを4096の構成にして、どちらのvlanもL2SWのfa1/3-4をNDPにしました。
この構成で障害試験を実施した場合、以下の結果となりました。
・片方のIF(fa1/1 or fa1/2)を閉塞した場合
トポロジが変更されず通信も不可状態。
・両方のIF(fa1/1 or fa1/2)を閉塞した場合
portchannel1がなくなりportchannel2の経路を通って通信可能。
よって、この構成でリンクアグリゲーションとPVSTの併用をした場合、切り替わりは起きないという結論に至りました。あくまでもループになるのを防ぐ役割としてPVSTを使用する認識です。
※追記
実機で同様の構成で試した結果、切り替わりが確認できました。GNS3だとなぜか切り替わらないようです。
投稿2019/08/18 04:15
編集2019/08/19 11:18
総合スコア172
あなたの回答
tips
プレビュー
バッドをするには、ログインかつ
こちらの条件を満たす必要があります。