03生成樹協議原理與應用(編輯修改稿)

　

【文章內容簡介】 配置信息與本地的一致，那么就可以認為該端口上所連接的交換機與本交換機處于同一個MST Region,運行相同的IST。,第52頁,MSTP運行示例IST,完成了如上的配置之后，經過BPDU的交流，IST就生成了，而各個instance也生成了獨立的生成樹(MSTI),SW1,SW2,SW3,首先劃分MST region,三臺交換機上分別創建了vlan 10,20,其中vlan10屬于instance 1，vlan 20屬于instance 2，配置如下： spanningmst configration instance 1 vlan 10 instance 2 vlan 20 name test (名稱自定義，但必須保持一致)可選配置 revision 1 （號碼必須保持一致）可選配置 配置三臺交換機上各實例的優先級 SW1 spanningtree instance 0 priority 4096 SW1 spanningtree instance 1 priority 4096 SW1 spanningtree instance 2 priority 8192 SW2 spanningtree instance 0 priority 8192 SW2 spanningtree instance 1 priority 8192 SW2 spanningtree instance 2 priority 4096 SW3上保持默認的優先級配置即32768,第53頁,MSTP運行示例IST,instace 0 的拓撲情況,SW1,SW3,SW2,instace 0 所對應的生成樹稱為CIST(Common Instance Spanning Tree),選舉根橋：SW1具有最高優先級4096選為根橋，SW2和SW3更新自己的配置消息。SW2（4096,1,8192） SW3（4096,1,32768） 選舉根端口：SW1是根橋，無根端口，其他交換機根據收到的最優配置信息的端口，設置根端口 選舉指定端口：根橋上的所有端口都為指定端口，在其他交換機上,比較在除根端口以外的其他端口上所收到的配置信息與自己的配置信息，如果自己的配置信息優于所接收到的配置信息，那么這個端口將被置為指定端口，否則被置為阻塞端口,根端口,指定端口,阻塞端口,,1,1,2,2,2,1,第54頁,MSTP運行示例IST,配置驗證,SW1 sh spanningtree mst 0 MST 0 vlans mapped : 19,1119,214094 BridgeAddr : 00d0.f8ff.a1a6 Priority : 4096 TimeSinceTopologyChange : 0d:0h:4m:37s TopologyChanges : 0 DesignatedRoot : 100000D0F8FFA1A6 RootCost : 0 RootPort : 0 CistRegionRoot : 100000D0F8FFA1A6 CistPathCost : 0,SW1sh spanningtree int f 0/1 MST 0 vlans mapped : 19,1119,214094 PortState : forwarding PortPriority : 128 PortDesignatedRoot : 100000D0F8FFA1A6 PortDesignatedCost : 0 PortDesignatedBridge : 100000D0F8FFA1A6 PortDesignatedPort : 8001 PortForwardTransitions : 1 PortAdminPathCost : 0 PortOperPathCost : 200000 PortRole : designatedPort SW1sh spanningtree int f 0/2 MST 0 vlans mapped : 19,1119,214094 PortState : forwarding PortPriority : 128 PortDesignatedRoot : 100000D0F8FFA1A6 PortDesignatedCost : 0 PortDesignatedBridge : 100000D0F8FFA1A6 PortDesignatedPort : 8002 PortForwardTransitions : 1 PortAdminPathCost : 0 PortOperPathCost : 200000 PortRole : designatedPort,第55頁,MSTP運行示例IST,配置驗證,SW2 sh spanningtree mst 0 MST 0 vlans mapped : 19,1119,214094 BridgeAddr : 00d0.f8b3.1f3c Priority : 8192 TimeSinceTopologyChange : 0d:0h:5m:46s TopologyChanges : 0 DesignatedRoot : 100000D0F8FFA1A6 RootCost : 0 RootPort : Fa0/1 CistRegionRoot : 100000D0F8FFA1A6 CistPathCost : 200000,SW2sh spanningtree int f 0/1 MST 0 vlans mapped : 19,1119,214094 PortState : forwarding PortPriority : 128 PortDesignatedRoot : 100000D0F8FFA1A6 PortDesignatedCost : 0 PortDesignatedBridge : 100000D0F8FFA1A6 PortDesignatedPort : 8002 PortForwardTransitions : 2 PortAdminPathCost : 0 PortOperPathCost : 200000 PortRole : rootPort SW2sh spanningtree int f 0/2 MST 0 vlans mapped : 19,1119,214094 PortState : forwarding PortPriority : 128 PortDesignatedRoot : 100000D0F8FFA1A6 PortDesignatedCost : 0 PortDesignatedBridge : 200000D0F8B31F3C PortDesignatedPort : 8002 PortForwardTransitions : 3 PortAdminPathCost : 0 PortOperPathCost : 200000 PortRole : designatedPort,第56頁,MSTP運行示例IST,配置驗證,SW3 sh spanningtree mst 0 MST 0 vlans mapped : 19,1119,214094 BridgeAddr : 00d0.f88c.17dc Priority : 32768 TimeSinceTopologyChange : 0d:0h:7m:11s TopologyChanges : 0 DesignatedRoot : 100000D0F8FFA1A6 RootCost : 0 RootPort : Fa0/1 CistRegionRoot : 100000D0F8FFA1A6 CistPathCost : 200000,SW3sh spanningtree int f 0/1 MST 0 vlans mapped : 19,1119,214094 PortState : forwarding PortPriority : 128 PortDesignatedRoot : 100000D0F8FFA1A6 PortDesignatedCost : 0 PortDesignatedBridge : 100000D0F8FFA1A6 PortDesignatedPort : 8001 PortForwardTransitions : 4 PortAdminPathCost : 0 PortOperPathCost : 200000 PortRole : rootPort SW3s