資深培訓(xùn)講師黑眼學(xué)習(xí)交流內(nèi)容

ConfiguringBasicConfiguringBasicBGPBasicBGPEbgp-Next-Peer-NetworkBGPNeighborBasicBGPBasicBGPBGP?ThiscommandentersBGP?Thiscommandentersrouterconfigurationmodeonly;subcommandsmustbeenteredtoactivateBGP.OnlyoneinstanceofBGPcanbeconfiguredontherouteratasingletime.Theautonomoussystemnumberidentifiestheautonomoussystemtowhichtherouterbelongs.??routerbgpautonomous-BGPneighborremote-asTheneighborBGPneighborremote-asTheneighborcommandactivatesaBGPsessionwiththisTheIPaddressthatisspecifiedisthedestinationaddressofBGPpacketsgoingtothisneighbor.ThisroutermusthaveanIPpathtoreachthisneighborbeforeitcansetupaBGPrelationship.statementstodetermineiftheneighborisaninternalorexternalThiscommandisusedforbothexternalandinternal如何確定兩臺BGP路由器是IBGP或EBGP鄰接關(guān)系Theremote-asoptionshowswhatASthisneighborisin.ThisASnumberisusedtodetermineiftheneighborisinternalorexternal.Theautonomoussystemnumberinthecommandthatrouterbgpautonomous-remote-asneighbor{ip-address|peer-group-name}remote-asautonomous-Example:BGPneighborASASExample:BGPneighborASASrouterbgpbgprouter-idneighborremote-asrouterbgpbgprouter-idneighborremote-asrouterbgpbgprouter-idneighborremote-asneighborremote-asupdate-source&ebgp-update-source&ebgp-BGPIssueswithSourceIProuterBGPIssueswithSourceIProuterbgpbgprouter-idneighborremote-asrouterbgpbgprouter-idneighborremote-asASWhencreatingaBGPtheneighborstatementdefinesthedestinationIPtheoutboundinterfacedefinesthesourceIPWhenaBGPpacketisreceivedforanewBGPsession,thesourceaddressofthepacketiscomparedtothelistofneighborstatements:Ifamatchisfound,arelationshipisIfnomatchisfound,thepacketisMakesurethatthesourceIPaddressmatchestheaddressthattheotherrouterhasinitsneighborstatement.Example:IBGPPeeringASASASExample:IBGPPeeringASASASToestablishtheIBGPsessionbetweenR6andR2,whichneighboraddressesshouldbeused?WhatIPaddressshouldR6useforpeeringwithR2?WhatIPaddressshouldR2useforpeeringwithR6?BGPneighborupdate-source?ThiscommandallowstheBGPprocesstousetheIPaddressofaspecifiedinterfaceasBGPneighborupdate-source?ThiscommandallowstheBGPprocesstousetheIPaddressofaspecifiedinterfaceasthesourceIPaddressofallBGPupdatestothatAloopbackinterfaceisusuallyused,becauseitwillbeavailableaslongastherouterisoperational.TheIPaddressusedintheneighborcommandontheotherrouterwillbethedestinationIPaddressofallBGPupdatesandshouldbetheloopbackinterfaceofthisrouter.Theneighborupdate-sourcecommandisnormallyusedonlywithIBGPTheaddressofanEBGPneighbormustbedirectlyconnectedbydefault;theloopbackofanEBGPneighborisnotdirectlyconnected.????neighbor{ip-address|peer-group-name}update-Example:BGPUsingLoopbackASASAS Example:BGPUsingLoopbackASASAS Lo0routerbgpbgprouter-idneighborremote-as65101routerbgpbgprouter-idneighborremote-as65101networknetworknetworknetworknetworknetworkExample:ebgp-multihopASASAS Example:ebgp-multihopASASAS routerbgpbgprouter-idneighborremote-asneighborebgp-multihop255routerbgpbgprouter-idneighborremote-asneighborebgp-multihop255BGPneighborebgp-multihopBGPneighborebgp-multihop??ThiscommandincreasesthedefaultofonehopforEBGPItallowsroutestotheEBGPloopbackaddress(whichwillhaveahopcountgreaterthan1).neighbor{ip-address|peer-group-name}ebgp-multihopNext-HopNext-HopNext-HopASASBGPNext-HopASASBGPisanAS-by-ASroutingprotocol,notarouter-by-routerroutingInBGP,thenexthopdoesnotmeanthenextrouter;itmeanstheIPaddresstoreachthenextAS.ForEBGP,thedefaultnexthopistheIPaddressoftheneighborrouterthatsenttheupdate.ForIBGP,theBGPprotocolstatesthatthenexthopadvertisedbyEBGPshouldbecarriedintoIBGP.next-ASASR3advertisesnetworktoR2next-ASASR3advertisesnetworktoR2inEBGP,withnexthopof.R2advertisesinIBGPtoR1,keepingasthenext-hopaddress.R1#shipBGPtableversionis1,localrouterIDisStatuscodes:ssuppressed,ddamped,hhistory,*valid,>best,i-internal,rRIB-failure,SOrigincodes:i-IGP,e-EGP,?-R2#shipBGPtableversionis2,localrouterIDisStatuscodes:ssuppressed,ddamped,hhistory,*valid,>best,i-internal,rRIB-failure,SOrigincodes:i-IGP,e-EGP,?-*NextHopMetricLocPrfWeight*>NextHopMetricLocPrfWeight00651020065102BGPneighbornext-hop-selfBGPneighbornext-hop-selfForcesallupdatesforthisneighbortobeadvertisedwiththisrouterasthenextTheIPaddressusedforthenext-hop-selfoptionwillbethesameasthesourceIPaddressoftheBGPpacket.neighbor{ip-address|peer-group-name}next-hop-Example:next-hop-selfASASrouterbgpR1觀察這條命令輸入前后，30.Example:next-hop-selfASASrouterbgpR1觀察這條命令輸入前后，/24R1#shipR2#shipBGPtableversionis2,localrouterIDisStatuscodes:ssuppressed,ddamped,hhistory,*valid,>best,BGPtableversionis2,localrouterIDisStatuscodes:ssuppressed,ddamped,hhistory,*valid,>best,i-internal,rRIB-failure,SOrigincodes:i-IGP,e-EGP,?-i-rRIB-failure,SOrigincodes:i-IGP,e-EGP,?-MetricLocPrfWeight*>NextHopMetricLocPrfWeight00651020065102NextHoponaMultiaccessThefollowingtakesplaceinamultiaccess?R6advertisesnetworktorouterR1inNextHoponaMultiaccessThefollowingtakesplaceinamultiaccess?R6advertisesnetworktorouterR1inEBGPwithnexthopofnotThisavoidsanBGPisbeingefficientbyinformingAS65100oftheASASR2#shrun|brbrouterbgpbgprouter-idneighborremote-as?bestentrypointAS65101fornetworkR6#shrun|brbrouterbgpneighborremote-asneighborremote-asAS?R6inAS65101alsoadvertisestoAS65100thebestentrypointforeachnetworkinAS65102istheR1#shrun|brnexthopofRouter2becausethatisthebestpathtomovethroughAS65101toAS65102.routerbgpneighborremote-asPeerPeerUsingaPeerThiscommandcreatesUsingaPeerThiscommandcreatesapeer?Thiscommanddefinesatemplatewithparameterssetforagroupofneighborsinsteadofindividually.Thiscommandisusefulwhenmanyneighborshavethesameoutboundpolicies.Memberscanhaveadifferentinboundpolicy.Updatesaregeneratedonceperpeergroup.Configurationis????neighborip-addresspeer-grouppeer-group-neighborpeer-group-namepeer-UsingaPeerR6UsingaPeerR6WithoutaPeerneighborremote-asR6UsingaPeerneighborinternalpeer-groupneighborinternalupdate-sourcelookup0neighborinternalnext-hop-selfneighborinternaldistribute-list20neighbornext-hop-neighbordistribute-list20neighborremote-asneighbornext-hop-neighbordistribute-list20neighborremote-asneighbornext-hop-neighbordistribute-list20neighborpeer-groupinternalneighborpeer-groupinternalneighborpeer-groupinternalBGPnetworkBGPnetworkBGPnetwork功能上ThisBGPnetwork功能上ThiscommandtellsBGPwhatnetworktoThecommanddoesnotactivatetheprotocolonan語法上Withoutamaskoption,thecommandadvertisesclassfulnetworks.Ifasubnetoftheclassfulnetworkexistsinaroutingtable,theclassfuladdressisannounced.Withthemaskoption,BGPlooksforanexactmatchinthelocalroutingtablebeforeannouncingtheroute.networknetwork-number[masknetwork-mask][route-Example:BGPnetworkTherouterExample:BGPnetworkTherouterlooksforexactly/24intheroutingtable,butcannotfindit,soitwillnotannounceanything.??Therouterlooksforexactly/16intheroutingIftheexactrouteisnotinthetable,youcanaddastaticroutetonull0sothattheroutecanbeworkmasknetworkmaskBGPNeighborBGPNeighborBGPNeighborBGPNeighborBGPauthenticationusesConfigureakey(password);routergeneratesamessagedigest,orhash,ofthekeyandthemessage.Messagedigestissent;keyisnotRoutergeneratesandcheckstheMD5digestofeverysegmentsentontheTCPconnection.Routerauthenticatesthesourceofeachroutingupdatepacketthatitreceivesneighbor{ip-address|peer-group-name}passwordExample:BGPNeighborASASExample:BGPNeighborASASrouterbgpneighborremote-as65000neighborpasswordrouterbgpneighborremote-as65500neighborpasswordBGPisconfiguredwithBGPisconfiguredwiththefollowingbasicBGP–––routerbgpautonomous-neighborip-addressremote-asautonomous-networknetwork-number[masknetwork-TheneighborcommandactivatesaBGPsessionwitha