1、實(shí)驗(yàn)一生成樹(shù)（STP）一、實(shí)驗(yàn)?zāi)康?）：本實(shí)驗(yàn)的目的是通過(guò)配置以下三種拓樸圖，讓我們對(duì)生成樹(shù)的工作原理有更深的認(rèn)識(shí)。2）:掌握生成樹(shù)在交換機(jī)上的配置方法，對(duì)生成樹(shù)在網(wǎng)絡(luò)上的應(yīng)用有更深的了解二、實(shí)驗(yàn)要求：1）：簡(jiǎn)述生成樹(shù)協(xié)議的三個(gè)前提。2）:簡(jiǎn)述根橋、根端口、指定端口的選舉原則。三、實(shí)驗(yàn)內(nèi)容：1、通過(guò)三種拓樸圖來(lái)研究根橋、根端口、指定端口選舉方法；2、根橋、根端口、指定端口查看方法四、實(shí)驗(yàn)步驟：第一種：實(shí)驗(yàn)拓樸：1）查看三臺(tái)交換機(jī)那個(gè)臺(tái)是根橋在交換機(jī)上使用命令showspanning-treevlan1或showspanning-treebrif可以查看當(dāng)前網(wǎng)絡(luò)中的根橋、根端口、指定端口。如下：

2、SWlflshspdlining-btiVLAfflSpanningtreeenabledprotocoliccc皿n昭nnnnnipr女ThisbridgeisrootFasiPthsmBtO/lHelloTime2secAge20srcForwardDelay15secBridgeIDPriority32768AddressccOO.0a30,0000EelloTime2secMaxAge20secForwardDelay15secAgingTime300Interface可編輯合同范本DesignatedNdmePortIDPrioCostICastBridgeIDPurlIDPatPt

3、KpynA+126,212019FWD10FVDSpanningtreeenabledprotocolieeeRooLIDPrioriLy32768AddressccOO.0&30.0000Cost19Port.2CFastEt.hernst0/1)HelloTime2secMaxAge20secForwardDelay15secBridgeIDPriority32768AddressHelloTime2secMaxAge20seeForwardDelay15secAgingTime30CSW2#tshspanning-treebriVLANIInterfaceNameDesignatedPo

4、rtII)PrioCostStsCostBridgfiIIPortIDFastEthemetO/1FantEthcrfictO/2FastEthemetO/1FantEthcrfictO/2可以看出SW!為根橋，SW2為非根橋，用同樣的命令查看第三臺(tái)交換機(jī)。2)現(xiàn)在修改SW2的優(yōu)先級(jí)讓它成為根橋在交換機(jī)上使用此命令spanning-treevlan1priority4096SW2(config)#spanning-treevlan1priority4096SW2#shspanning-treebri查看spanning-treeSVSItshspanRing-treebriVLAN1Spann

5、ingtreeenabledprotocolieeeRootIDPriority4096AddressThisbridgelbtherootHelloTime2secMaxAge20secForwardDelay15secBridgeIDPriority4096AddressHelloTime2seehkxAge20seeForwardDelay15seeAgingTine300InterfaceDesignatedNamePortIDPrioCostStsCostBridgeIDPortID第二種：實(shí)驗(yàn)拓樸FastEthernetO/1126.212819FIDFastEthernetO/2

6、128.312819FWD04096ccOO.0f91DODO12&31）查看二臺(tái)交換機(jī)那個(gè)臺(tái)是根橋在交換機(jī)上使用命令showspanning-treevlan1或showspanning-treebrif可以查看當(dāng)前網(wǎng)絡(luò)中的根橋、根端口、指定端口。SI2咖hgpanning-treebriVLAN1SpanningRootIDtreeenabledprotocolieeePricrity32768kAddressCost19Port2(FastEthernetO/1)HelloTime2secUaxAge20Priority32768AddreccccOOllOeS.0000HelloTim

7、e9secUaxKge20AingTime300BridgeIDsecForwardsecForwardDelay15Delay15secsecTnt.ftrfaceNamePortIDFrioCostStsDfisignatedCostBridgeIDPortID2a:b:FastEthernelO/1FastEUiernelO/2可以看到交換機(jī)SW2上的)128.2128128.3126FO/1是轉(zhuǎn)發(fā)狀態(tài),19FWD019BLK0F0/2是阻斷狀態(tài)。c:指定為根端口方法有：改變接口上的cost值（在本端修改）命令為spanning-treevlan1cost20改變發(fā)送者接口上ID值（在對(duì)

8、端修改）命令為spanning-treevlan1port-priority96注：port-priority后的值是16倍數(shù)在物理上改變?cè)谶@就不作詳解了。步聚如下：第一種方法：在本端修改接口cost值SW2(config)#intfa0/1SW2(config-if)#spanning-treevlan1cost20SW2#shspanning-treebriSI2UshspanningtreebriVLAN1InterfaceNajnePortIDFrioCostDesignatedStsCostBridgeIDPortIDForwardDelay15secSpanringtreeenab

9、ledprotocolieeeRootIDPriorityAddressCostPortHelloTime32758193(FastEthernetO/2)2secMaxA前20secBridgeIDPriority32768AddressccOO.la48.0000HelloTime3sec血掘Age20setAgingTime300ForwardDelay15secFastEthernetO/1128.212820BLK03276&FVD第二種方法：在對(duì)端修改發(fā)送者接口ID值SW1(config)#intfaO/2SW1(config-if)#spanning-treevlan1priority96SW2#shspanning-treebri(在對(duì)端查看)第三種：實(shí)驗(yàn)拓樸1)在一臺(tái)交換上要修改根端口，則