單元1配置交換機(jī)任務(wù)12配置生成樹任務(wù)情景祥云公司由于交換機(jī)數(shù)量的增加和連接的復(fù)雜性，交換機(jī)之間具有冗余鏈路本來是一件很好的事情，但是它有可能引起的問題比它能夠解決的問題還要多。如果準(zhǔn)備兩條以上的路，就必然形成一個環(huán)路，交換機(jī)并不知道如何處理環(huán)路，只有周而復(fù)始地轉(zhuǎn)發(fā)幀，形成一個“死環(huán)路”，這個死環(huán)路會造成整個網(wǎng)絡(luò)處于阻塞狀態(tài)，導(dǎo)致網(wǎng)絡(luò)癱瘓。采用生成樹協(xié)議可以避免環(huán)路。任務(wù)拓?fù)?，如圖1-12-1所示。拓?fù)湔f明：交換機(jī)2臺、PC機(jī)2臺、Console線1根、網(wǎng)線6根圖

1-12-1網(wǎng)絡(luò)拓?fù)?/p>

任務(wù)情景

任務(wù)需求1.按照拓?fù)鋱D連接網(wǎng)絡(luò)。2.交換機(jī)端口規(guī)劃見表1-12-1。

表1-12-1交換機(jī)端口規(guī)劃SW-1SW-2SW-1SW-2PC1SW-1PC2SW-1PC3SW-2PC4SW-2如果多實例生成樹成功，則通過Showspanning-treemst觀察到不同實例中trunk鏈路的阻塞狀況，實現(xiàn)VLAN100只通過23口，VLAN200只通過24口，用多實例生成樹完成數(shù)據(jù)流量的負(fù)載均衡。了解生成樹的作用及應(yīng)用配置生成樹學(xué)習(xí)目標(biāo)任務(wù)分析默認(rèn)下交換機(jī)所有端口屬于VLAN1，并分別在兩臺交換機(jī)連接PC1和PC2作為測試，當(dāng)沒有在交換機(jī)上啟用生成樹協(xié)議時，用兩條網(wǎng)絡(luò)連接兩臺交換機(jī)將導(dǎo)致形成廣播風(fēng)暴，不一會兒，交換機(jī)出現(xiàn)死機(jī)狀態(tài)，PC1和PC2不能正常通信，因此必須在兩臺交換機(jī)啟用生成樹協(xié)議來阻止因交換機(jī)物理環(huán)路死機(jī)的現(xiàn)象。預(yù)備知識生成樹協(xié)議（英語：SpanningTreeProtocol，STP），是一種工作在OSI網(wǎng)絡(luò)模型中的第二層(數(shù)據(jù)鏈路層)的通信協(xié)議，基本應(yīng)用是防止交換機(jī)冗余鏈路產(chǎn)生的環(huán)路.用于確保以太網(wǎng)中無環(huán)路的邏輯拓?fù)浣Y(jié)構(gòu).從而避免了廣播風(fēng)暴,大量占用交換機(jī)的資源。多生成樹協(xié)議MSTP（MultipleSpanningTreeProtocol）是IEEE802.1s中定義的生成樹協(xié)議，通過生成多個生成樹，來解決以太網(wǎng)環(huán)路問題。在以太網(wǎng)中部署MSTP協(xié)議后可實現(xiàn)如下功能：形成多棵無環(huán)路的樹，解決廣播風(fēng)暴并實現(xiàn)冗余備份；多棵生成樹在VLAN間實現(xiàn)負(fù)載均衡，不同VLAN的流量按照不同的路徑轉(zhuǎn)發(fā)。任務(wù)實施第1步：正確連接網(wǎng)線，恢復(fù)出廠設(shè)置之后，配置交換機(jī)的VLAN信息，配置端口到vlan的映射關(guān)系。SW-1：SW-1#configSW-1(Config)#vlan10SW-1(Config-VLAN10)#switchportinterfaceethernet1/0/1-10SettheportEthernet1/0/1accessvlan10successfullySettheportEthernet1/0/2accessvlan10successfullySettheportEthernet1/0/3accessvlan10successfullySettheportEthernet1/0/4accessvlan10successfullySettheportEthernet1/0/5accessvlan10successfullySettheportEthernet1/0/6accessvlan10successfullySettheportEthernet1/0/7accessvlan10successfullySettheportEthernet1/0/8accessvlan10successfullySettheportEthernet1/0/9accessvlan10successfullySettheportEthernet1/0/10accessvlan10successfully任務(wù)實施SW-1(Config-VLAN10)#exitSW-1(Config)#vlan20SW-1(Config-VLAN20)#switchportinterfaceethernet1/0/11-20SettheportEthernet1/0/11accessvlan20successfullySettheportEthernet1/0/12accessvlan20successfullySettheportEthernet1/0/13accessvlan20successfullySettheportEthernet1/0/14accessvlan20successfullySettheportEthernet1/0/15accessvlan20successfullySettheportEthernet1/0/16accessvlan20successfullySettheportEthernet1/0/17accessvlan20successfullySettheportEthernet1/0/18accessvlan20successfullySettheportEthernet1/0/19accessvlan20successfullySettheportEthernet1/0/20accessvlan20successfullySW-1(Config-VLAN20)#exitSW-1(Config)#interfaceethernet1/0/23-24SW-1(Config-If-Port-Range)#switchportmodetrunkSettheportEthernet1/0/23modeTRUNKsuccessfullySettheportEthernet1/0/24modeTRUNKsuccessfullySW-1(Config-If-Port-Range)#exitSW-1(Config)#任務(wù)實施SW-2：SW-2#configSW-2(Config)#vlan10SW-2(Config-VLAN10)#switchportinterfaceethernet1/0/1-10SettheportEthernet1/0/1accessvlan10successfullySettheportEthernet1/0/2accessvlan10successfullySettheportEthernet1/0/3accessvlan10successfullySettheportEthernet1/0/4accessvlan10successfullySettheportEthernet1/0/5accessvlan10successfullySettheportEthernet1/0/6accessvlan10successfullySettheportEthernet1/0/7accessvlan10successfullySettheportEthernet1/0/8accessvlan10successfullySettheportEthernet1/0/9accessvlan10successfullySettheportEthernet1/0/10accessvlan10successfullySW-2(Config-VLAN10)#exit任務(wù)實施SW-2(Config)#vlan20SW-2(Config-VLAN20)#switchportinterfaceethernet1/0/11-20SettheportEthernet1/0/11accessvlan20successfullySettheportEthernet1/0/12accessvlan20successfullySettheportEthernet1/0/13accessvlan20successfullySettheportEthernet1/0/14accessvlan20successfullySettheportEthernet1/0/15accessvlan20successfullySettheportEthernet1/0/16accessvlan20successfullySettheportEthernet1/0/17accessvlan20successfullySettheportEthernet1/0/18accessvlan20successfullySettheportEthernet1/0/19accessvlan20successfullySettheportEthernet1/0/20accessvlan20successfullySW-2(Config-VLAN20)#exitSW-2(Config)#interfaceethernet1/0/23-24SW-2(Config-If-Port-Range)#switchportmodetrunkSettheportEthernet1/0/23modeTRUNKsuccessfullySettheportEthernet1/0/24modeTRUNKsuccessfullySW-2(Config-If-Port-Range)#exitSW-2(Config)#任務(wù)實施第2步：配置多實例生成樹，在SW-1、SW-2上分別將

vlan10映射到實例1上；將vlan20映射到實例2上SW-1：SW-1(Config)#spanning-treemstconfigurationSW-1(Config-Mstp-Region)#namemstpSW-1(Config-Mstp-Region)#instance1vlan10SW-1(Config-Mstp-Region)#instance2vlan20SW-1(Config-Mstp-Region)#exitSW-1(Config)#spanning-treeMSTPisstartingnow,pleasewait...........MSTPisenabledsuccessfully.

SW-2：SW-2(Config)#spanning-treemstconfigurationSW-2(Config-Mstp-Region)#namemstpSW-2(Config-Mstp-Region)#instance1vlan10SW-2(Config-Mstp-Region)#instance2vlan20SW-2(Config-Mstp-Region)#exitSW-2(Config)#spanning-treeMSTPisstartingnow,pleasewait...........MSTPisenabledsuccessfully.任務(wù)實施第3步：在根交換機(jī)中配置端口在不同實例中的優(yōu)先級，確保不同實例阻塞不同端口查找根交換機(jī)：SW-1#showspanning-tree--MSTPBridgeConfigInfo--

Standard:IEEE802.1sBridgeMAC:00:03:0f:0b:f8:12BridgeTimes:MaxAge20,HelloTime2,ForwardDelay15ForceVersion:3

###########################Instance0###########################SelfBridgeId:32768-00:03:0f:0b:f8:12RootId:thisswitchExt.RootPathCost:0RegionRootId:thisswitchInt.RootPathCost:0RootPortID:0CurrentportlistinInstance0:…………任務(wù)實施從show中可以看出，SW-1是根交換機(jī)，在根交換機(jī)上修改trunk端口在不同實例中的優(yōu)先級。SW-1(Config)#interfaceethernet1/0/23SW-1(Config-If-Ethernet1/0/23)#spanning-treemst1port-priority32SW-1(Config-If-Ethernet1/0/23)#exitSW-1(Config)#interfaceethernet1/0/24SW-1(Config-If-Ethernet1/0/24)#spanning-treemst2port-priority32SW-1(Config-If-Ethernet1/0/24)#exitSW-1(Config)#任務(wù)實施第4步：配置SW-2的loopback端口，驗證多實例生成樹，配置SW-2上各vlan所屬loopback端口，保證各vlan在線。

SW-2(Config)#interfaceethernet1/0/1SW-2(Config-If-Ethernet1/0/1)#loopbackSW-2(Config-If-Ethernet1/0/1)#exitSW-2(Config)#interfaceethernet1/0/11SW-2(Config-If-Ethernet1/0/11)#loopbackSW-2(Config-If-Ethernet1/0/11)#exit

任務(wù)實施用“showspanning-treemst”，觀察各現(xiàn)象：SW-1#showspanning-treemst###########################Instance0###########################vlansmapped:1-9;11-19;21-4094SelfBridgeId:32768.00:03:0f:0b:f8:12RootId:thisswitchRootTimes:MaxAge20,HelloTime2,ForwardDelay15,maxhops20PortNameIDExtRPCIntRPCStateRoleDsgBridgeDsgPort-----------------------------------------------------------------------Ethernet1/0/1128.00100FWDDSGN32768.00030f0bf812128.001Ethernet1/0/11128.00900FWDDSGN32768.00030f0bf812128.009Ethernet1/0/23128.02300FWDDSGN32768.00030f0bf812128.023Ethernet1/0/24128.02400FWDDSGN32768.00030f0bf812128.024###########################Instance1###########################vlansmapped:10SelfBridgeId:32768-00:03:0f:0b:f8:12RootId:thisswitchPortNameIDIntRPCStateRoleDsgBridgeDsgPort--------------------------------------------------------------Ethernet1/0/1128.0010FWDDSGN32768.00030f0bf812128.001Ethernet1/0/23032.0230FWDDSGN32768.00030f0bf812032.023Ethernet1/0/24128.0240FWDDSGN32768.00030f0bf812128.024###########################Instance2###########################vlansmapped:20SelfBridgeId:32768-00:03:0f:0b:f8:12RootId:thisswitchPortNameIDIntRPCStateRoleDsgBridgeDsgPort--------------------------------------------------------------Ethernet1/0/11128.0090FWDDSGN32768.00030f0bf812128.009Ethernet1/0/23128.0230FWDDSGN32768.00030f0bf812128.023Ethernet1/0/24032.0240FWDDSGN32768.00030f0bf812032.024任務(wù)實施SW-2(config)#shspanning-treemst###########################Instance0###########################vlansmapped:1-9;11-19;21-4094SelfBridgeId:32768.00:03:0f:0f:6e:adRootId:32768.00:03:0f:0b:f8:12RootTimes:MaxAge20,HelloTime2,ForwardDelay15,maxhops19PortNameIDExtRPCIntRPCStateRoleDsgBridgeDsgPort-----------------------------------------------------------------------Ethernet1/0/1128.0010200000FWDDSGN32768.00030f0f6ead128.001Ethernet1/0/11128.0090200000FWDDSGN32768.00030f0f6ead128.009Ethernet1/0/22128.0220200000FWDDSGN32768.00030f0f6ead128.022Ethernet1/0/23128.02300FWDROOT32768.00030f0bf812128.023Ethernet1/0/24128.02400BLKALTR32768.00030f0bf812128.024###########################Instance1###########################vlansmapped:10SelfBridgeId:32768-00:03:0f:0f:6e:adRootId:32768.00:03:0f:0b:f8:12PortNameIDIntRPCStateRoleDsgBridgeDsgPort--------------------------------------------------------------Ethernet1/0/1128.001200000FWDDSGN32768.00030f0f6ead128.001Ethernet1/0/23128.0230FWDROOT32768.00030f0bf812032.023Ethernet1/0/24128.0240BLKALTR32768.00030f0bf812128.024###########################Instance2###########################vlansmapped:20SelfBridgeId:32768-00:03:0f:0f:6e:adRootId:32768.00:03:0f:0b:f8:12PortNameIDIntRPCStateRoleDsgBridgeDsgPort------------------------------