关于.VSS的双活检测

.6/6VSS技术2011-09-2913:50:50标签：VSSSSONSFMECdual-activeSTPHSRPPagpLACPVSS设计与配置一,VSS技术介绍VSS称为虚拟交换技术,它的功能是将多台ciscocatalyst6500交换机虚拟成单台交换机,VSS使用机箱间NSF/SSO作为两台机箱间的主要高可用性机制,当一个虚拟交换机成员发生故障时,网络中无需进行协议重收敛。一个虚拟交换机成员机箱将作为主用虚拟交换机成员,另一成员将处于控制面板的热等待状态。请注意,这两个机箱的数据面板均可用,因此总流量转发能力为1440Gbps。当一个虚拟交换机成员发生故障时,网络中无需进行协议重收敛,接入层或核心层交换机继续转发流量,因为它们只会检测出EtherChannel捆绑中有一个链路故障,所以不需要重收敛任何协议,通过VSS传输的流量不会发生任何中断。在传统模式中,一台交换机发生故障就会导致STP、HSRP和路由协议等多个控制协议进行收敛,与之相比,交换机故障时VSS机制远要出色得多。多机箱EtherChannel〔MEC是一种L2多路径技术。这类EtherChannel形式允许相连节点在构成VSS的两个物理CiscoCatalyst6500系列交换机间端接EtherChannel,从而创建简单的无环路L2拓扑结构。在VSS拓扑结构中使用MEC,能使所有链路激活,并同时在不采用生成树协议的情况下,提供高度可用的拓扑结构。二,VSS设计

默认情况下,2个VSS机箱的引擎之间的冗余机制是NSF/SSO,NSF/SSO支持状态信息和配置同步。另外,2个VSS机箱的引擎之间只有运行在NSF/SSO模式下,备份机箱引擎的PFC卡,SwitchFabric卡和线路卡及其DFC才能是活动状态。若主备机箱的信息不匹配〔如主备机箱引擎的IOS版本不一致,则2个VSS机箱的引擎之间的冗余机制是RPR,运行在RPR模式下,只有配置能够同步,但备用机箱引擎的PFC卡,SwitchFabric卡和线路卡及其DFC卡都是非活动状态。在2个VSS机箱之间通过RoleResolutionProtocol<RRP>协商每个VSS机箱的角色

<activeorstandby>后,会执行acrosstheVSLswitches配置的一致性以确保正确的SL操作,如下是配置一致性需要检查的条目：另外,在NSF/SSO模式下,IOS的版本及其补丁和PFC运行模式需要一致,PFC的模式可以通过命令更改。三,VSS基本配置步骤一：定义VSSdomainID&switchIDStandaloneSwitch1:SW1#configtSW1<config>#switchvirtualdomain10SW1<config-vs-domain>#switch1StandaloneSwitch2:SW2#configtSW2<config>#switchvirtualdomain10SW2<config-vs-domain>#switch2步骤二：ConfigurePrioritySettings<Optional>

高优先级交换机,成为active,低优先级的交换机成为standby。若优先级一样,则SwitchID小的为active,switchID大的为standby。StandaloneSwitch1:SW1<config-vs-domain>#switch1priority110SW1<config-vs-domain>#switch2priority100StandaloneSwitch2:SW2<config-vs-domain>#switch1priority110SW2<config-vs-domain>#switch2priority100步骤三：ConfiguretheVirtualSwitchLink<VSL>VSL是一个有特殊用途的EthernetChannel链路,包含一个或多个〔最多8个物理端口。VSL作用有二：1、其中只选择一个物理成员接口作为控制链路,承载机箱之间的系统控制信息2、这其余的物理成员接口承载网络控制信息,当必要时也可以承载普通数据流量StandaloneSwitch1:SW1#configtSW1<config>#interfaceport-channel1SW1<config-if>#noshutSW1<config-if>#switchvirtuallink1SW1<config-if>#intrangeTen5/4-5SW1<config-if-range>#channel-group1modeonStandaloneSwitch2:SW2#configtSW2<config>#interfaceport-channel2SW2<config-if>#noshutSW2<config-if>#switchvirtuallink2SW2<config-if>#intrangeTen5/4–5SW2<config-if-range>#channel-group2modeonSinceVSLEtherChannelusesLMPpermemberlink,thelink-aggregationprotocols,suchasPAgPandLACP,arenotrequired;eachmemberlinkmustbeconfiguredinunconditionalEtherChannelmodeusingthechannel-groupgroup-numbermodeoncommand.步骤4：ExecutingtheConversion执行转换进程,在特权模式下执行switchconvertmodevirtual命令,这样做将转换端口名称为3元素形式"interface-typeswitch-number/slot/port",然后保存配置,重启设备。重启设备的作用：12个配置合并为1个配置2为端口重新编号从slot/port到switch-number/slot/port3>只有重启设备,才能通过NSF/SSO协商A/S角色StandaloneSwitch1:SW1#convertmodevirtualThiscommandwillconvertallinterfacenamestonamingconvention"interface-typeswitch-number/slot/port",savetherunningconfigtostartup-configandreloadtheswitch.Doyouwanttoproceed?[yes/no]:yesConvertinginterfacenamesBuildingconfiguration...StandaloneSwitch2:SW2#switchconvertmodevirtualThiscommandwillconvertallinterfacenamestonamingconvention"interface-typeswitch-number/slot/port",savetherunningconfigtostartup-configandreloadtheswitch.Doyouwanttoproceed?[yes/no]:yesConvertinginterfacenamesBuildingconfiguration...步骤5：CompletingtheConversion最后一步需要在ActiveVirtualSwitch上执行"switchacceptmodevirtual"命令自动配置StandbyVirtualSwitchVSSActiveVirtualSwitch:VSS#switchacceptmodevirtualDoyouwanttoproceed?[yes/no]:yesMergingthestandbyVSLconfiguration…Buildingconfiguration...[OK]或者在Switch1〔Active上重新配置Switch2的VSLVSSActiveVirtualSwitch:vss-sw1<config>#interfaceport-channel2vss-sw1<config-if>#noshutvss-sw1<config-if>#switchvirtuallink2vss-sw1<config>#interfaceten2/5/4vss-sw1<config-if>#channel-group2modeonvss-sw1<config>#interfaceten2/5/5vss-sw1<config-if>#channel-group2modeon到此已经把两台独立的物理6500s配置成VSS,这是给新的VSS配置一个Hostname,然后保存配置。VSSActiveVirtualSwitch:vss-sw1#conftEnterconfigurationcommands,oneperline.EndwithCNTL/Z.vss-sw1<config>#hostnameSW65VSSSW65VSS<config>#^ZSW65VSS#00:13:40:%SYS-5-CONFIG_I:ConfiguredfromconsolebyconsoleSW65VSS#wrBuildingconfiguration...00:16:23:%PFINIT-SP-5-CONFIG_SYNC:Sync'ingthestartupconfigurationtothestandbyRouter.[OK]SW65VSS#VSS状态检查VSSActiveVirtualSwitch:SW65VSS#shswitchvirtualSwitchmode:VirtualSwitchLocalswitchnumber:1Localswitchoperationalrole:VirtualSwitchActivePeerswitchnumber:2Peerswitchoperationalrole:VirtualSwitchStandbySW65VSS#shswitchvirtuallinkVSLStatus:UPVSLUptime:18:36:43UTCApr62007VSLSCPPing:PassVSLICCPing:PassVSLControlLink:Te1/5/4SW65VSS#shswitchvirtualroleVSS—Multi-ChassisEtherChannelPAgPConfigurationandMonitoring配置连接到接入交换机3560使用PAgP的Trunk类型的EtherChannel,建议对MEC链路运行TrunkDesirable-Desirable。VSSActiveVirtualSwitch:interfacerangeGigabitEthernet1/3/1

InterfaceonVSS-SW1descriptionAccessSwitchFacingInterfaceswitchportswitchporttrunkencapsulationdot1qswitchportmodedynamicdesirableTrunkmoddynamicanddesirableswitchporttrunkallowedvlan8,9OnlyallowneedVLANsforagiventrunkloggingeventlink-statusLoggingforlinkstatusloggingeventtrunk-statusLoggingfortrunkstatusloggingeventbundle-statusLoggingforport-channelstatuschannel-protocolpagpchannel-group202modedesirableDefinePort-channel,PAgPmodedesirableVSSActiveVirtualSwitch:interfaceGigabitEthernet2/3/1

InterfaceonVSS-SW2descriptionAccessSwitchFacingInterfaceswitchportswitchporttrunkencapsulationdot1qswitchportmodedynamicdesirableTrunkmoddynamicanddesirableswitchporttrunkallowedvlan8,9OnlyallowneedVLANsforagiventrunkloggingeventlink-statusLoggingforlinkstatusloggingeventtrunk-statusLoggingfortrunkstatusloggingeventbundle-statusLoggingforport-channelstatuschannel-protocolpagpchannel-group202modedesirableinterfacePort-channel202AutomaticallycreatedbydefiningatinterfacesdescriptionAccessSwitchMECswitchportswitchporttrunkencapsulationdot1qswitchporttrunkallowedvlan8,9loggingeventlink-statusloggingeventspanning-treestatusSTPloggingenabledonport-channelLACPConfigurationandMonitoring配置连接到服务器使用LACP的Trunk类型的EtherChannel,同时使能STPportfastVSSActiveVirtualSwitch:interfacerangeGigabitEthernet1/4/40,GigabitEthernet2/4/40descriptionServerFacingInterfacenoshutswitchport

loggingeventlink-statusLoggingforlinkstatusloggingeventbundle-statusLoggingforport-channelstatuschannel-protocollacpchannel-group100modeactiveDefinePort-channel,lacpmodeactiveinterfacePort-channel100AutomaticallycreatedbydefiningatinterfacesdescriptionAccessSwitchMECswitchportspanning-treeportfast四、VSS双活检测设计&配置VSSDual-ActiveSupervisorsVSL链路丢失和恢复：如果VSL出现故障,则备用机箱无法确定活动机箱的状态。为了确保发生切换而不出现延迟,备用机箱假设活动机箱已发生故障,并启动切换来接管活动角色。如果原始活动机箱仍运行正常,则两个机箱此时均处于活动状态。此情形称为双活动情形。双活动情形会对网络稳定性产生不利影响,因为两个机箱均会使用相同的IP地址、SSH密钥和STP网桥ID。虚拟交换系统<VSS>必须检测双活动情形,并执行恢复操作。VSS支持增强的PAgP、IP双向转发检测<BFD>和dual-activefast-hello三种方法,以便检测双活动情形。建议：如有可能,请同时启用基于ePAgP和直接心跳链路的VSLPFastHello方法。Fast-HelloConfigurationandMonitoringVSSActiveVirtualSwitch:SW65VSS#switchvirtualdomain10SW65VSS<config-vs-domain>#dual-activedetectionfast-helloSW65VSS<config>#intgi1/4/48SW65VSS<config-if>#dual-activefast-helloSW65VSS<config-if>#intgi2/4/48SW65VSS<config-if>#dual-activefast-hello%VSDA-SW2_SPSTBY-5-LINK_UP:InterfaceGi1/5/1isnowdual-activedetectioncapable%VSDA-SW1_SP-5-LINK_UP:InterfaceGi2/5/1isnowdual-activedetectioncapableSW65VSS#showswitchvirtualdual-activefast-helloSW65VSS#remotecommandstandby-rpshowswitchvirtualdual-activefast-helloePAgPConfigu