中生成树协议的配置

1、一、实验目的1）：本实验的目的是通过配置以下三种拓朴图，让我们对生成树的工作原理有更 深的认识。2）:掌握生成树在交换机上的配置方法，对生成树在网络上的应用有更深的了解二、实验要求：1）：简述生成树协议的三个前提。2）:简述根桥、根端口、指定端口的选举原则。三、实验内容：1、通过三种拓朴图来研究根桥、根端口、指定端口选举方法；2、根桥、根端口、指定端口查看方法四、实验步骤：第一种：实验拓朴：1）查看三台交换机那个台是根桥在交换机上使用命令show spanning-tree vlan 1 或 show spanning-tree brif可以查看当前网络中的根桥、根端口、指定端口。如下：SWl

2、flsh spdlining-btiVLAfflSpanning tree enabled protocol icccFoot ID Priority 32768Addiess ccOO. 0a30. 00000 32768 ccOO. 0a3Q. 0000 128. 2 n皿 n昭n nnnn ipr 女This bridge is rootHello Time2 secAge 20 srcForward Delay 15 secBridge IDPriority32768AddressccOO. 0a30, 0000Eello Time2 sec Max Age20secForwardDe

3、lay15 secAging Time300InterfaceDesignatedNdmePort ID Prio Cost ；StsCastBridgeIDPurl IDFasiPthsmBtO/lPa t Pt Kp ynA +126,2 12019 FWD10 FVDSW2#tsh spann i ng-tree briSpanningtree enabledprotocol ieeeRooL IDPriori Ly32768AddressccOO. 0a30. 0000Cost19Port.2 CFastEthrnetO/1)Hello Time2 sec Max Age 20sec

4、ForwardDelay15 secBridge IDPriority32768AddressccOO. 0190. 0000Hello Time2 sec Max Ago 20sec ForwardDelay15 secAging Time30CInterfaceDesignatedNamePort 11) Prio Cost StsCost Bridgfi【）FastEt hfrnetO/11 湘.2128伯F町0 32768ccOO. 0a30. 000DFastHthcrnctO/2128.3128IS) RLK19 32768ccOO. 0c24. DOODVLAN1Port ID1

5、28. 212乩3可以看出SW为根桥，SW2为非根桥，用同样的命令查看第三台交换机。2)现在修改SW2的优先级让它成为根桥在交换机上使用此命令spa nnin g-tree vlan 1 priority 4096SW2(co nfig)# spa nnin g-tree vlan 1 priority 4096SW2#sh spanning-tree bri查看 spanning-treeSVSItsh span Ring-tree briVLAN1Spanning tree enabled protocol ieeeRoot IDPriority4096AddressccOO. 0f90.

6、 ODDOThis bridgelb the rootHello Time2 sec Max Age 20 secForward Delay 15 secBridge IDPriority4096AddressccOO. 0f90. GOODHello Time2 see hkx Age 20 seeForward Delay 15 seeAging Tine300InterfaceDesignatedNamePort ID Prio Cost Sts Cost Bridge IDPort IDFastEthernetO/1126.212819 FID0 4096 ccOO. Of 91 DO

7、DO 128.2FastEthernetO/2128.312819 FWD0 4096 ccOO. 0f91 DODO 12& 3第二种：实验拓朴1）查看二台交换机那个台是根桥在交换机上使用命令show spanning-treevlan 1 或 show spanning-treebrif可以查看当前网络中的根桥、根端口、指定端口。SI2咖h gpanning-tree briVLAN1 Spanning Root IDtree enabledprotocol ieeePricrity32768kAddressccOO. 0380. 0000Cost19Port2 (FastEthernet

8、O/1)Hello Time2 sec Uax Age 20Priority32768AddreccccOOl lOeS. 0000Hello Time9 sec Uax Kge 20Aing Time300Bridge IDsec Forwardsec ForwardDelay 15Delay 15secsecTnt.ftrfaceNamePort ID Frio Cost StsDfisignatedCostBridgeIDPort ID2a:b:FastEthernelO/1FastEUiernelO/2可以看到交换机SW2上的)128.2128128.3126FO/1是转发状态,19

9、FWD019 BLK0F0/2是阻断状态。32768 ccOO. 0380. 0000 128.232768 ccOO. 0360. 0000 123.3c:3指定为根端口方法有：改变接口上的cost值（在本端修改）命令为 spanning-tree vlan 1 cost 20 改变发送者接口上ID值（在对端修改）命令为 spanning-tree vlan 1 port-priority 96 注：port-priority后的值是16倍数在物理上改变在这就不作详解了。步聚如下：第一种方法：在本端修改接口cost值SW2(co nfig)# int fa0/1SW2(co nfig-if)

10、# spa nnin g-tree vlan 1 cost 20SW2#sh spa nnin g-tree briSI2Ush spanningtree briVLAN1InterfaceNajnePort ID Frio CostDesignatedSts Cost Bridge IDPort IDSpanring tree enabled protocol ieeeRoot IDPriorityAddressCostPortHello Time32758ccOD.Uk. 0000193 (FastEthernetO/2)2 sec Max A前 20 secBridge IDPriori

11、ty32768AddressccOO. la48. 0000Hello Time3 sec 血掘 Age 20 setAging Time300Forward Delay 15 secForward Delay 15 secFastEthernetO/1128.212820 BLK0 3276&ccOO, laic. 0000 128.2FastEthernet0/2128.312819 FVD0 32768ccOO. laic. 9000 128.3第二种方法：在对端修改发送者接口ID值SW1(config ) #int faO/2SW1 (con fig-if)#spa nnin g-tree vla n 1 prio