CCNA (640-802)教学培训课件：9-VLAN Trunk

---VLANTrunkCCNA(640-802)

多个交换机上的VLAN应用FastEthernet工程VLAN市场VLAN会计VLAN1楼2楼3楼交换机之间的VLAN通信3－1VLAN1VLAN2VLAN3VLAN1VLAN2VLAN3如何实现交换机之间的VLAN通信？每个VLAN一条链路？如果有100个VLAN怎么办呢？交换机之间的VLAN通信3－2VLAN1VLAN2VLAN3VLAN1VLAN2VLAN3如何实现交换机之间的VLAN通信？只使用一条链路，那么来自多个VLAN的数据如何标识？交换机之间的VLAN通信3－3例如：三个分别来自1、2、3班级的学生，到另一个学校去，分别要参观1、2、3班的上课情况，对方的学校怎么识别他们分别应该去哪个班级？出发前加个标识，再把标识的方法告诉对方！①②③VLAN标识交换机给每个去往其他交换机的数据帧打上VLAN标识VLAN1VLAN2VLAN3VLAN1VLAN2VLAN3中继链路（Trunk）接入链路（Access）VLAN1标记VLAN3标记VLAN标识的种类以太网上实现中继可用两种封装类型ISL（Cisco私有协议）IEEE802.1QIEEE802.1Q的工作原理和帧格式2－1中继链路接入链路802.1Q标记4字节IEEE802.1Q的工作原理和帧格式2－2标准以太网帧TPIDPriorityCFIVLAN

IDTCI12bit，可标识的VLANID为4096个DataDASATypeCRCDataDASATypeCRCTag带有IEEE802.1Q标记的以太网帧CiscoISL工作原理和帧格式3－1中继链路VLAN2接入链路ISL头26字节CRC4字节CiscoISL工作原理和帧格式3－2DASA以太类型/长度数据CRC26字节ISL头4字节ISL尾CiscoISL工作原理和帧格式3－340位4位4位48位16位24位24位DATYPEUSERSALENSNAP/LLCHSA15位1位16位16位可变长度32位VLANIDBPDUINDEX保留被封装的帧CRCISL和802.1Q的异同相同点都是显式标记，即帧被显式标记了VLAN的信息不同点IEEE802.1Q是公有的标记方式，ISL是Cisco私有的ISL采用外部标记的方法，802.1Q采用内部标记的方法ISL标记的长度为30字节，802.1Q标记的长度为4字节中继的几种模式和协商2－1VLAN1VLAN2VLAN3模式为Access动态：可以成为Trunk动态：希望成为Trunk模式为Trunk中继的几种模式和协商2－2模式模式说明开启（on）将端口设置为永久中继模式关闭（off）将端口设置为永久非中继模式企望（desirable）让端口主动试图将链路转变成中继端口自动（auto）使该端口愿意将链路变成中继链路配置接口为Trunk模式Switch(config)#interfaceinterface-idSwitch(config-if)#switchportmode?

accessSettrunkingmodetoACCESSunconditionallydynamicSettrunkingmodetodynamicallynegotiateaccessortrunkmodetrunkSettrunkingmodetoTRUNKunconditionallySwitch(config-if)#switchportmodetrunk接口为接入模式接口为动态协商模式接口为中继模式配置接口为动态协商模式Switch(config-if)#switchportmodedynamic?autoSettrunkingmodedynamicnegotiationparametertoAUTOdesirableSettrunkingmodedynamicnegotiationparametertoDESIRABLE自动企望查看接口模式Switch#showinterfaceinterface-idswitchportName:Fax/xSwitchport:EnabledAdministrativeMode:dynamicdesirableOperationalMode:downAdministrativeTrunkingEncapsulation:dot1qNegotiationofTrunking:OnAccessModeVLAN:1(default)TrunkingNativeModeVLAN:1(default)VoiceVLAN:noneAdministrativeprivate-vlanhost-association:noneAdministrativeprivate-vlanmapping:noneOperationalprivate-vlan:noneTrunkingVLANsEnabled:ALLPruningVLANsEnabled:2-1001CaptureModeDisabledCaptureVLANsAllowed:ALL接口模式缺省为dynamicdesirable封装类型为802.1q配置VLANTrunk实例VLAN1VLAN2VLAN3VLAN1VLAN2VLAN3Port1－3Port4－10Port11－23Port24Port24SW1配置VLANTrunk4－1第一步：在交换机上添加VLANSW1#vlandatabaseSW1(vlan)#vlan2VLAN2added:Name:VLAN0002SW1(vlan)#vlan3VLAN3added:Name:VLAN0003SW1(vlan)#exitAPPLYcompleted.Exiting....配置VLANTrunk

4－2第二步：将接口添加到相应的VLAN中SW1#configterminalSW1(config)#interfacerangef0/4-10SW1(config-if-range)#switchportaccessvlan2SW1(config)#interfacerangef0/11-23SW1(config-if-range)#switchportaccessvlan3配置VLANTrunk

4－3第三步：配置交换机之间互联的端口为TrunkSW1(config)#interfacef0/24SW1(config-if)#switchportmodetrunk配置VLANTrunk

4－4VLAN1VLAN2VLAN3VLAN1VLAN2VLAN3Port1－3Port4－10Port11－23Port24Port24Port1Port2－10Port11-23SW2请学员完成配置查看端口状态SW1#showinterfacef0/24switchportName:Fa0/24Switchport:EnabledAdministrativeMode:trunkOperationalMode:trunkAdministrativeTrunkingEncapsulation:dot1qOperationalTrunkingEncapsulation:dot1qNegotiationofTrunking:OnAccessModeVLAN:1(default)TrunkingNativeModeVLAN:1(default)VoiceVLAN:noneAdministrativeprivate-vlanhost-association:noneAdministrativeprivate-vlanmapping:noneOperationalprivate-vlan:noneTrunkingVLANsEnabled:ALLPruningVLANsEnabled:2-1001CaptureModeDisabledCaptureVLANsAllowed:ALL接口模式配置为Trunk接口工作模式为TrunkTrunk协议类型为802.1qTrunk可以承载所有的VLAN从Trunk中添加、删除Vlan去除VLAN

Switch(config-if)#switchporttrunkallowedvlanremove

vlan-list添加VLANSwitch(config-if)#switchporttrunkallowedvlanadd

vlan-list

检查中继端口允许VLAN的列表Switch#showinterfaceinterface-idswitchport从Trunk中删除Vlan配置实例SW1(config-if)#switchporttrunkallowedvlanremove2SW1(config-if)#endSW1#showinterfacef0/24switchportName:Fa0/24Switchport:EnabledAdministrativeMode:trunkOperationalMode:trunkAdministrativeTrunkingEncapsulation:dot1qOperationalTrunkingEncapsulation:dot1qNegotiationofTrunking:OnAccessModeVLAN:1(default)TrunkingNativeModeVLAN:1(default)VoiceVLAN:noneAdministrativeprivate-vlanhost-association:noneAdministrativeprivate-vlanmapping:noneOperationalprivate-vlan:noneTrunkingVLANsEnabled:1,3-1005PruningVLANsEnabled:2-