Notaios6

VistageraldosmecanismoskeepalivenoCiscoIOSndiceIntroduoInformaesdeApoioMecanismosdokeepalivedeinterfaceInterfacesdeEthernetInterfacesseriaisManutenesdeatividadedeHDLCManutenesdeatividadedePPPInterfacesdotúnelGREKeepalivescriptoKeepalivesdeIKEKeepalivesNATIntroduoEstedocumentodescreveosváriosmecanismoskeepalivenodoCiscoIOS.
InformaesdeApoioOsmensagensdekeepalivesoenviadosporumdispositivoderedeatravésdeumexameoudeunscircuitosvirtuaisafiminformaraindaumoutrodispositivoderedeesseocircuitoentreelesfunes.
ParaqueoKeepalivestrabalhehádoisfatoresessenciais:Ointervalokeepaliveéoperíododetempoentrecadamensagemdekeepalivequeéenviadoporumdispositivoderede.
Istoésempreconfigurável.
qAsnovastentativasdokeepalivesoonúmerodevezesqueodispositivocontinuaaenviarapacoteskeepalivesemrespostaantesqueoestadoestejamudadoa"parabaixo".
ParaalgunstiposdeKeepalivesistoéconfigurável,quandoparaoutrohouverumvalorpadroquenopossasermudado.
qMecanismosdokeepalivedeinterfaceInterfacesdeEthernetEmmeiosdetransmissotaiscomoumEthernet,oKeepalivesélevementeoriginal.
DesdequehámuitospossíveisvizinhosnosEthernet,okeepalivenoestáprojetadodeterminarseotrajetoaqualquerumvizinhoespecíficonofioestádisponível.
Projeta-sesomentecertificar-sedosistemalocaltenhaoacessodeleituraegravaoaofiodosEthernetpróprio.
OroteadorproduzumpacotedeEthernetcomsecomooendereoMACdeorigemededestinoeumcódigotipodeEthernetespecialde0x9000.
OhardwaredeEthernetenviaestepacotenofiodosEtherneteentorecebeimediatamenteestapartetraseiradopacoteoutravez.
IstoverificaohardwaredeemissoedereceponoadaptadordoEtherneteaintegridadebásicadofio.
InterfacesseriaisAsinterfacesserialpodemtertiposdiferentesdeencapsulamentosecadatipodeencapsulamentodeterminaotipodoKeepalivesqueseráusado.
InscrevaocomandokeepalivenomododeconfiguraodainterfaceafimajustarafrequênciaemqueumroteadorenviapacotesECHOREQaseupar:Afimrestaurarosistemaaointervalokeepalivedopadrodossegundos10,inscrevaocomandokeepalivecomnenhumapalavra-chave.
qAfimdesabilitaroKeepalives,inscrevaocomandodisabledokeepalive.
qNota:keepaliveOcomandoaplica-seàsinterfacesserialqueusamolinkdedadosdenívelelevadoContol(HDLC)ouoencapsulamentoPPP.
NoseaplicaàsinterfacesserialqueusamoEncapsulamentoframerelay.
Nota:ParaoPPPeostiposdoencapsulamentodeHDLC,umkeepalivedezerodesabilitaoKeepaliveseérelatadonocomandoshowrunning-configoutputcomoodesabilitaodokeepalive.
ManutenesdeatividadedeHDLCUmoutromecanismokeepaliveconhecidoémanutenesdeatividadeserialparaoHDLC.
AsmanutenesdeatividadeserialsoenviadasparaafrenteeparatrásentredoisRoteadoreseoKeepalivessoreconhecidos.
Comousodosnúmerosdesequênciaseguircadakeepalive,cadadispositivopodeconfirmarseéparHDLCrecebeuokeepalivequeenviou.
ParaoencapsulamentodeHDLC,trêsKeepalivesignoradosfazemcomquearelaosejaderrubada.
PermitaocomandodebugserialinterfaceparaumaconexodeHDLCafimpermitirqueousuárioveroKeepalivesqueégeradoeenviado:SampleOutput:17:21:09.
685:Serial0/0:HDLCmyseq0,mineseen0*,yourseen1,lineupAsmanutenesdeatividadedeHDLCcontêmtrêspartesafimdeterminá-lotrabalham:O"myseq"queénossopróprionúmerodeincremento.
qO"mineseen"queérealmenteumreconhecimentodooutrolado(incrementado)quedizqueesperaestenúmerodenós.
q"Yourseen"queénossoreconhecimentoaooutrolado.
qNota:Quandoadiferenanosvaloresnoscamposdomyseqedomineseenexcedetrêsnoroteador2,alinhavaiparabaixoearelaoérestaurada.
DesdequeasmanutenesdeatividadedeHDLCsotipoKeepalivesECHOREQ,afrequênciadekeepaliveéimportanteerecomenda-sequecombinamacimaexatamenteemambososlados.
Seostemporizadoressoforadasincronizao,osnúmerosdesequênciacomeamsairdaordem.
Porexemplo,sevocêajustaumladoaossegundos10eooutroa25segundos,aindapermitiráarelaopermaneaacimaenquantoadiferenanafrequêncianoésuficienteparafazercomqueosnúmerosdesequênciaestejamporumadiferenadetrês.
ComoumailustraodecomoasmanutenesdeatividadedeHDLCtrabalham,oroteador1eoroteador2soconectadosdiretamenteatravésdoSerial0/0edoSerial2/0respectivamente.
AfimilustrarcomooKeepalivesfalhadoHDCLéusadoparaseguirosestadosdarelao,oSerial0/0seráfechadonoroteador1.
Roteador1Router1#showinterfacesserial0/0/0Serial0/0/0isup,lineprotocolisup(connected)HardwareisHD64570Internetaddressis10.
0.
0.
1/8MTU1500bytes,BW64Kbit,DLY20000usec,rely255/255,load1/255EncapsulationHDLC,loopbacknotset,keepaliveset(10sec)[outputisomited]17:21:09.
685:Serial0/0:HDLCmyseq0,mineseen0*,yourseen1,lineup17:21:19.
725:Serial0/0:HDLCmyseq1,mineseen1*,yourseen2,lineup17:21:29.
753:Serial0/0:HDLCmyseq2,mineseen2*,yourseen3,lineup17:21:39.
773:Serial0/0:HDLCmyseq3,mineseen3*,yourseen4,lineup17:21:49.
805:Serial0/0:HDLCmyseq4,mineseen4*,yourseen5,lineup17:21:59.
837:Serial0/0:HDLCmyseq5,mineseen5*,yourseen6,lineup17:22:09.
865:Serial0/0:HDLCmyseq6,mineseen6*,yourseen7,lineup17:22:19.
905:Serial0/0:HDLCmyseq7,mineseen7*,yourseen8,lineup17:22:29.
945:Serial0/0:HDLCmyseq8,mineseen8*,yourseen9,lineupRouter1(config-if)#shut17:22:39.
965:Serial0/0:HDLCmyseq9,mineseen9*,yourseen10,lineup17:22:42.
225:%LINK-5-CHANGED:InterfaceSerial0/0,changedstatetoadministrativelydown17:22:43.
245:%LINEPROTO-5-UPDOWN:LineprotocolonInterfaceSerial0/0,changedstatetodownRoteador2Router2#showinterfacesserial0/0/0Serial0/0/0isup,lineprotocolisup(connected)HardwareisHD64570Internetaddressis10.
0.
0.
2/8MTU1500bytes,BW64Kbit,DLY20000usec,rely255/255,load1/255EncapsulationHDLC,loopbacknotset,keepaliveset(10sec)[outputisomited]17:21:04.
929:Serial2/0:HDLCmyseq0,mineseen0,yourseen0,lineup17:21:14.
941:Serial2/0:HDLCmyseq1,mineseen1*,yourseen1,lineup17:21:24.
961:Serial2/0:HDLCmyseq2,mineseen2*,yourseen2,lineup17:21:34.
981:Serial2/0:HDLCmyseq3,mineseen3*,yourseen3,lineup17:21:45.
001:Serial2/0:HDLCmyseq4,mineseen4*,yourseen4,lineup17:21:55.
021:Serial2/0:HDLCmyseq5,mineseen5*,yourseen5,lineup17:22:05.
041:Serial2/0:HDLCmyseq6,mineseen6*,yourseen6,lineup17:22:15.
061:Serial2/0:HDLCmyseq7,mineseen7*,yourseen7,lineup17:22:25.
081:Serial2/0:HDLCmyseq8,mineseen8*,yourseen8,lineup17:22:35.
101:Serial2/0:HDLCmyseq9,mineseen9*,yourseen9,lineup17:22:45.
113:Serial2/0:HDLCmyseq10,mineseen10*,yourseen10,lineup17:22:55.
133:Serial2/0:HDLCmyseq11,mineseen10,yourseen10,lineup17:23:05.
153:HD(0):Resetfrom0x20375817:23:05.
153:HD(0):AssertingDTR17:23:05.
153:HD(0):AssertingDTRandRTS17:23:05.
153:Serial2/0:HDLCmyseq12,mineseen10,yourseen10,lineup17:23:15.
173:HD(0):Resetfrom0x20375817:23:15.
173:HD(0):AssertingDTR17:23:15.
173:HD(0):AssertingDTRandRTS17:23:15.
173:Serial2/0:HDLCmyseq13,mineseen10,yourseen10,linedown17:23:16.
201:%LINEPROTO-5-UPDOWN:LineprotocolonInterfaceSerial2/0,changedstatetodownRouter2#17:23:25.
193:Serial2/0:HDLCmyseq14,mineseen10,yourseen10,linedownManutenesdeatividadedePPPAsmanutenesdeatividadedePPPsoumpoucodiferentesdasmanutenesdeatividadedeHDLC.
AocontráriodoHDLC,asmanutenesdeatividadedePPPsomaiscomosibilos.
Osambososladospodemsibilar-seemseulazer.
OmovimentonegociadoapropriadoéresponderSEMPREaeste"sibilo".
AssimparamanutenesdeatividadedePPP,afrequênciaouovalordetemporizadorsosomentelocalmenterelevanteenotêmnenhumimpactonooutrolado.
MesmoseumladodesligaoKeepalives,aindaRESPONDER2aquelasrequisiesdeecodoladoquetemumtemporizadordekeepalive.
Contudo,nuncainiciaráalgumadoseuspróprios.
PermitaocomandodebugppppacketparaumaconexoPPPafimpermitirqueousuárioverasmanutenesdeatividadedePPPquesoenviadas:Router2#showinterfacesserial0/0/0Serial0/0/0isup,lineprotocolisup(connected)HardwareisHD64570Internetaddressis10.
0.
0.
2/8MTU1500bytes,BW64Kbit,DLY20000usec,rely255/255,load1/255EncapsulationHDLC,loopbacknotset,keepaliveset(10sec)[outputisomited]17:21:04.
929:Serial2/0:HDLCmyseq0,mineseen0,yourseen0,lineup17:21:14.
941:Serial2/0:HDLCmyseq1,mineseen1*,yourseen1,lineup17:21:24.
961:Serial2/0:HDLCmyseq2,mineseen2*,yourseen2,lineup17:21:34.
981:Serial2/0:HDLCmyseq3,mineseen3*,yourseen3,lineup17:21:45.
001:Serial2/0:HDLCmyseq4,mineseen4*,yourseen4,lineup17:21:55.
021:Serial2/0:HDLCmyseq5,mineseen5*,yourseen5,lineup17:22:05.
041:Serial2/0:HDLCmyseq6,mineseen6*,yourseen6,lineup17:22:15.
061:Serial2/0:HDLCmyseq7,mineseen7*,yourseen7,lineup17:22:25.
081:Serial2/0:HDLCmyseq8,mineseen8*,yourseen8,lineup17:22:35.
101:Serial2/0:HDLCmyseq9,mineseen9*,yourseen9,lineup17:22:45.
113:Serial2/0:HDLCmyseq10,mineseen10*,yourseen10,lineup17:22:55.
133:Serial2/0:HDLCmyseq11,mineseen10,yourseen10,lineup17:23:05.
153:HD(0):Resetfrom0x20375817:23:05.
153:HD(0):AssertingDTR17:23:05.
153:HD(0):AssertingDTRandRTS17:23:05.
153:Serial2/0:HDLCmyseq12,mineseen10,yourseen10,lineup17:23:15.
173:HD(0):Resetfrom0x20375817:23:15.
173:HD(0):AssertingDTR17:23:15.
173:HD(0):AssertingDTRandRTS17:23:15.
173:Serial2/0:HDLCmyseq13,mineseen10,yourseen10,linedown17:23:16.
201:%LINEPROTO-5-UPDOWN:LineprotocolonInterfaceSerial2/0,changedstatetodownRouter2#17:23:25.
193:Serial2/0:HDLCmyseq14,mineseen10,yourseen10,linedownerespostasquesorecebidas:Router2#showinterfacesserial0/0/0Serial0/0/0isup,lineprotocolisup(connected)HardwareisHD64570Internetaddressis10.
0.
0.
2/8MTU1500bytes,BW64Kbit,DLY20000usec,rely255/255,load1/255EncapsulationHDLC,loopbacknotset,keepaliveset(10sec)[outputisomited]17:21:04.
929:Serial2/0:HDLCmyseq0,mineseen0,yourseen0,lineup17:21:14.
941:Serial2/0:HDLCmyseq1,mineseen1*,yourseen1,lineup17:21:24.
961:Serial2/0:HDLCmyseq2,mineseen2*,yourseen2,lineup17:21:34.
981:Serial2/0:HDLCmyseq3,mineseen3*,yourseen3,lineup17:21:45.
001:Serial2/0:HDLCmyseq4,mineseen4*,yourseen4,lineup17:21:55.
021:Serial2/0:HDLCmyseq5,mineseen5*,yourseen5,lineup17:22:05.
041:Serial2/0:HDLCmyseq6,mineseen6*,yourseen6,lineup17:22:15.
061:Serial2/0:HDLCmyseq7,mineseen7*,yourseen7,lineup17:22:25.
081:Serial2/0:HDLCmyseq8,mineseen8*,yourseen8,lineup17:22:35.
101:Serial2/0:HDLCmyseq9,mineseen9*,yourseen9,lineup17:22:45.
113:Serial2/0:HDLCmyseq10,mineseen10*,yourseen10,lineup17:22:55.
133:Serial2/0:HDLCmyseq11,mineseen10,yourseen10,lineup17:23:05.
153:HD(0):Resetfrom0x20375817:23:05.
153:HD(0):AssertingDTR17:23:05.
153:HD(0):AssertingDTRandRTS17:23:05.
153:Serial2/0:HDLCmyseq12,mineseen10,yourseen10,lineup17:23:15.
173:HD(0):Resetfrom0x20375817:23:15.
173:HD(0):AssertingDTR17:23:15.
173:HD(0):AssertingDTRandRTS17:23:15.
173:Serial2/0:HDLCmyseq13,mineseen10,yourseen10,linedown17:23:16.
201:%LINEPROTO-5-UPDOWN:LineprotocolonInterfaceSerial2/0,changedstatetodownRouter2#17:23:25.
193:Serial2/0:HDLCmyseq14,mineseen10,yourseen10,linedownAsmanutenesdeatividadedePPPcontêmtrêspartes:NúmerodeID-usadoparaidentificaraqueoECHOREQoparresponde.
qTipokeepalive-OECHOREQéKeepalivesenviadopelodispositivodeorigemeoqECHOREPérespostasenviadaspelopar.
Númerosmágicos-asnotificaesincluemosnúmerosmágicosdoserveredoclienteremoto.
OparvalidaonúmeromágiconopacotederequisiodeecoLCP,etransmiteopacotederespostadeecocorrespondenteLCPquecontémonúmeromágiconegociadopeloroteador.
qParaoencapsulamentoPPP,cincoKeepalivesignoradosfazemcomquearelaosejaderrubadaInterfacesdotúnelGREOmecanismokeepalivedotúnelGREélevementediferentedoqueparaEthernetouinterfacesserial.
DáacapacidadeparaqueumladoorigineerecebapacoteskeepaliveaedeumroteadorremotomesmoseoroteadorremotonoapoiamanutenesdeatividadedeGRE.
DesdequeoGREéummecanismodetunelamentodopacoteparaescavarumtúneloIPdentrodoIP,umpacotedotúnelIPGREpodeserconstruídodentrodeumoutropacotedotúnelIPGRE.
ParamanutenesdeatividadedeGRE,asPRE-construesdoremetenteopacotedarespostadekeepalivedentrodopacotederequisiodokeepaliveoriginaldemodoqueasnecessidadesdaextremidaderemotasomentedefazerodesencapsulamentoGREpadrodocabealhoIPexteriorGREeenviamentoopacoteGREinternoIP.
Estemecanismofazcomquearespostadekeepaliveenvieparaforaainterfacefísicaumpoucodoqueainterfacedetúnel.
ParamaisdetalhesaotrabalhardoKeepalivesdotúnelGRE,vejacomoasmanutenesdeatividadedeGREtrabalham.
KeepalivescriptoKeepalivesdeIKEOKeepalivesdoInternetKeyExchange(IKE)éummecanismousadoparadeterminarseumparVPNpodeascendenteereceberotráfegocriptografado.
OKeepalivescriptoseparadoéexigidoalémdoquekeepalivesdeinterfaceporqueosparesVPNgeralmentesoconectadosnuncadevoltaàpartetraseira,assimqueoskeepalivesdeinterfacenofornecembastanteinformaosobreoestadodoparVPN.
EmdispositivosIOSCisco,oskeepalivesdeIKEsopermitidospelousodeummétodoproprietáriochamadooDeadPeerDetection(DPD).
AfimpermitirqueogatewayenvieDPDaopar,incorporeestecomandoaomododeconfiguraoglobal:cryptoisakmpkeepaliveseconds[retry-seconds][periodic|on-demand]AfimdesabilitaroKeepalives,use"no"oformuláriodestecomando.
Paraobtermaisinformaessobredoquecadapalavra-chavenestecomandofaz,vejaokeepalivecriptodoisakmp.
Paramaisgranularidade,oKeepalivespodeigualmenteserconfiguradosoboperfilISAKMP.
Paramaisdetalhes,vejao[CiscoIOSIPsec]davistageraldoperfilISAKMP.
KeepalivesNATEmcasodasencenaesondeumparVPNestáatrásdeumNetworkAddressTranslation(NAT),NAT-Traversaléusadoparaacriptografia.
Contudo,duranteperíodosociososépossívelqueaentradaNATnodispositivoascendentepdecronometrarparafora.
IstopodecausarproblemasquandovocêtrazacimaotúneleoNATnoébidirecional.
OKeepalivesNATépermitidoafimmanterotraodinmicoNATvivoduranteumaconexoentredoispares.
OKeepalivesNATépacotesdeUDPcomumpayloadunencrypteddeumbyte.
EmboraaaplicaoatualDPDsejasimilaraoKeepalivesNAT,háumapequenadiferena-oDPDestáusadoparadetectarostatusdepeerquandooKeepalivesNATforenviadoseaentidadedoIPsecnoenviounemrecebeuopacoteemumperíododetempoespecificado.
Ointervaloválidoestáentre5a3600segundos.
Dica:SeoKeepalivesNATestápermitido(atravésdocomandokeepalivenatdoisamkpcripto),osusuáriosdevemassegurar-sedequeovalorinativosejamaiscurtodoqueotempodeexpiraodomapeamentoNATde20segundos.
Paraobtermaisinformaessobredestacaracterística,vejaatransparênciadeNATdoIPsec.