V4ACITDM 4 0 L3 multicast over multisite

JohnWeston,TechnicalMarketingEngineer,DCTG,October2018,ACI4.0Multi-SiteL3Multicast,ACI4.0addssupportforL3multicastoverMulti-SiteRequiresexternalRPAllsitesmusthavereachabilitytocommonRPviaeachsiteslocalL3outsSupportssourcesattachedtofabric(asanEP)andsourceoutsideoffabric(reachablevialocalL3out)ExternalsourcesmustbereachableindependentlyfromeachsitevialocalL3Outs.ExternalsourceInter-sitemulticastisnotsupportedMulticasttrafficisalwayssenttoremotesiteswhereVRFisdeployedwhetherthereisgroupinterestornot.ThisissimilartocurrentL2multicastbehaviorNotsupportedon1stGenleafswitches(currentL3multicastlimitation),MulticastRoutingwithMulti-Siteguidelinesandlimitations,L3multicastisalwaysforwardedusingtheVRFGIPotreesL3multicastwithinasiteisforwardedtoallleafswitcheswheretheVRFisdeployedwhetherthereismulticastinterestornot.MulticastisdroppedattheegressleafinthecasewheretherearenointerestedreceiversInter-siteL3multicastisforwardedtoallsitesoverintheVRFGIPousingtheHER(headendreplication)tunnelwhetherthereismulticastinterestornotatthereceivingsite.Multicastisdroppedatthereceivingspineiftherearenointerestedreceiversatthesite.,MulticastRoutingwithMulti-Siteforwardingbehavior,MulticastRoutingoverMulti-siteExternalRPrequirementwith4.0,Inter-SiteNetwork,Site1,Siten,L3out-1,RPmustbeexternaltothefabricAllsitescanpointtothesameRPaddress,RP:1.1.1.1,L3out-2,PIM,RP:1.1.1.1,RP:1.1.1.1,MulticastRoutingoverMulti-siteExternalRPrequirementwith4.0,Inter-SiteNetwork,Site1,Siten,L3out-1,SitescanbeconnectedtodifferentRPaddresseswithinter-domainmulticast,RP:1.1.1.1,L3out-2,MSDP,RP:2.2.2.2,RP:1.1.1.1,RP:2.2.2.2,MulticastFlows,MulticastRoutingoverMulti-siteSourcesoutsidereceiversinside,Inter-SiteNetwork,Site1,Siten,L3out-1,L3out-2,source,receiver,receiver,EachsitemustreceivemulticastsentfromexternalsourcesvialocalL3out,Multicasttrafficfromexternalsourcesisdroppedonspine.NotsentoverHREPtunnels,Multicasttrafficfromexternalsourcesisdroppedonspine.NotsentoverHREPtunnels,RP,MulticastRoutingoverMulti-siteSourcesoutsidereceiversinsidewithtransitcase,Inter-SiteNetwork,Site1,Siten,L3out-1,L3out-2,Transitmulticastusecaseissupported.OnesitecanbetransitforanexternalsourceandthatmulticastflowcanarriveatanothersiteviathelocalL3out.MulticastisnotsentovertheISNinthiscase.,receiver,receiver,L3out-3,source,Multicasttrafficfromexternalsourcesisdroppedonspine.NotsentoverHREPtunnels,Multicasttrafficfromexternalsourcesisdroppedonspine.NotsentoverHREPtunnels,RP,MulticastRoutingoverMulti-siteSourcesinsideandreceiversinside,Inter-SiteNetwork,Site1,Siten,RP,source,BL11,BL12,BL21,BL22,Multicastdata,PIMjoin,PIMregister,(*,G)Join,(*,G)Join,SourceinsideandreceiverinsidewillbefloodedintheVRFwithinthesiteandsentovertheHREPtunnelinter-site.,receiver,MulticastRoutingoverMulti-siteSourcesinsideandreceiversinside(cont),Inter-SiteNetwork,Site1,Siten,RP,source,BL11,BL12,BL21,BL22,Multicastdata,PIMjoin,PIMregister,(*,G)Join,WhenRPreceivesregisterfromsourceitwillforwardmulticastdownthesharedtree.WhenBL(BL22)installs(S,G)itwillseethatsourceisapervasiveBDandwillsendprunetowardsRP.Multicastreceivermaytemporarilyreceiveduplicatepackets.,receiver,PIMPrune,PIMPrune,MulticastRoutingoverMulti-siteSourcesinsideandreceiversoutside,Inter-SiteNetwork,Site1,Siten,L3out-1,L3out-2,RP,source,BL11,BL12,BL21,BL22,Multicastdata,PIMjoin/prune,PIMregister,Receiveroutsidecanreceivemulticastfromeithersite.Thesitewherethe(S,G)joinisreceivedisdeterminedbytheexternalmulticastdevicesbasedonshortestpath/loadbalancing,etc.Notinfabriccontrol,receiver,receiver,192.168.10.1,192.168.10.0/24,192.168.10.0/24,UnicastUnicasttransitacrosssitesnotsupportedEndpointsinasitemustuselocalL3Outfortrafficexitingthefabric.MulticastReceiversinasitewithexternalsourcesmustreceivemulticastfromL3OutsinthelocalsiteSourcesinasitecansendmulticasttoexternalreceiversviathelocalL3OutorviaL3Outsindifferentsites,DifferencesbetweenMulti-Siteunicastandmulticastflows4.0release,Multicastforwarding,StretchedBDswithIntersiteBUMTrafficEnabled(noPIM)WithinasitethemulticastwillbesenttotheBDGIPomulticastaddressMulticastacrosssiteswillbesentintheHREPtunneltotheremotesitemulticastTEPaddressAtthereceivingspinethemulticastwillbesentdowntheFTAGtreetothereceivingsiteBDGIPomulticastaddressVXLANheaderwillcarrytheBDVNID,L2multicastoverMulti-site(supportedfrom3.0),Inter-SiteNetwork,Site1,Site2,BD1,BD1,BD1,Site1BD1VNID16514962BD1GIPo225.0.195.240,Site2multicastTEP:10.100.102.200,BD1VNID16711545HREPtunneldest:10.100.102.200,Site2BD1VNID16711545BD1GIPo225.1.128.160,Source,Receiver,Review,L3multicastoverMulti-siteforwardingbehavior,Inter-SiteNetwork,Site1,Site2,BD1,BD2,BD2,Site2multicastTEP:10.100.102.200,L3MulticastisalwayssenttotheVRFGIPowithinasite(existingbehavior)CrosssiteL3multicastwillalsobesentintheVRFGIPo.BetweensitesitissentovertheHREPtunneltothemulticastTEPoftheremotesite.TheVXLANheaderwillincludethesourcesiteVRFVNID.L3MulticastatthereceivingsitewillbesentintheVRFGIPoofthereceivingsite,Source,Receiver,BD1,Source,VRF,VRF,VRF,VRF,VRF,VRF,L3Out,L3Out,VRF,VRF,Site1VRFVNID2293762VRFGIPo225.1.248.32,Site2VRFVNID2621443VRFGIPo225.1.248.16,Site1VRFVNID229.3762HREPtunneldest:10.100.102.200,4.0,RP,MulticasttrafficwillalwaysberoutedwhenPIMisenabledforaBD.Thisincludesintra-BDIPmulticast(L2multicast)Intra-BDIPmulticastforwardingbehavior(sameascurrentbehaviorforsinglesite)*WillbeforwardedinVRFGIPoRequiresRPforASMmulticastgroupsTTLwillbedecremented(ingressleafandegressleafonly).SourceMACwillbeBDMACaddress,L2multicastwithPIMenabledBDwithMulti-Site,Inter-SiteNetwork,Site1,Site2,BD1,Site2multicastTEP:10.100.102.200,Source,Receiver,BD1,Source,VRF,VRF,VRF,VRF,L3Out,L3Out,VRF,VRF,Site1VRFVNID2293762VRFGIPo225.1.248.32,Site2VRFVNID2621443VRFGIPo225.1.248.16,Site1VRFVNID229.3762HREPtunneldest:10.100.102.200,Receiver,BD1,VRF,DecrementTTL,DecrementTTL,*Note:Doesnotapplyforsourceandreceiversonsameleaf,RP,MSOConfiguration,ThefollowingmulticastsettingsareavailablefromtheMSOL3MulticastVRFsettingL3MulticastBDsettingEPGInter-SitemulticastsourceTheVRFandBDsettingsenabletherespectiveAPICsettingsTheEPGinter-SitemulticastsourceknobisanMSOonlysetting.UsedforEPGsthatarenotstretchedacrosssites.MSOwillcreateashadowEPGonallsiteswhereVRFisstretched.L3Out,RP,PIMandIGMPconfigurationsaresitelocalandnotmanagedfromMSO,Multi-SiteOrchestratorConfiguration,MSOMulticastVRFsetting,L3MulticastmustbeenabledonVRFbeforeenablingBDs,MSOMulticastBD/EPGsettings