欢迎来到天天文库
浏览记录
ID:38793466
大小:1.13 MB
页数:13页
时间:2019-06-19
《Google-1014-Poutievski-Introducing_fail-open_mode英文学习资料》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、FailOpen:AWaytoHandleCPNFailuresLeonPoutievski10/16/2014IntroductionWithSDN,controllerrunsremotelyfromtheswitches.Manybenefits:●Complexroutingmovestothepowerfulserver●Simplerswitch●Simplerupgrade●EasiertointroducenewfeaturesOut-of-bandCPNAseparateout-of-bandcontrolplanenetwork(CPN)makesbootstrap
2、pingandtroubleshootingsimpler.Problem:PartialCPNFailureControllerlosesconnectivityofaswitch.IfcontrollertreatsCPNdisconnectasswitchdown:●Controllerreroutetrafficfromthenode●MassivechurnonCPNdisconnect●MassivechurnonCPNre-connectresultingincongestionandtrafficloss.CPNControllerSignalsHowcanthecon
3、trollerdistinguishdisconnectednodefromadownnode?●Peerswitchesknowaboutadjacentlinks○Ifneighboringswitchreportsportstothedisconnectednodearedown,thenthenodeislikelydown●ControllercansendinjectprobestodetermineifpathsthroughtheCPNdisconnectednodearestillup●End-to-enddatamightbeavailable,e.g.hostma
4、yseedropsAssumptionsFrequentswitchupdatesarenotrequired●E.g.proactiveapproach:switchisupdatedbasedontopologychanges,routesadvertisement,trafficchanges●Example:WANSwitchescanautomaticallyreactonlocalfailures.E.g.prunedownports.CPNFail-OpenGoal:MinimizethenetworkdisruptionduringandafterCPNfailures
5、Fail-Open-OptimisticPolicyAssumethedataplaneisnotaffectedbycontrolplanefailures.Controllerknowslastprogrammedstate,assumesthatnodeis“frozen”atthatstate.Fail-OpenReaction:AtTransitKeepusingtheconfirmedflowsonEncapfailed-opennodes.Newroutingsolutionscanusetheconfirmedflowsonfailed-openednodes.Enca
6、pTransitDecapCPNFail-OpenReaction:DestinationKeepusingtheconfirmedflowsonEncapTransitfailed-opennodes.Newroutingsolutionscanusetheconfirmedflowsonfailed-openednodes.EncapTransitDecapCPNFail-OpenReaction:AtSourceKeepusingtheconfirmedflowsonEncapfailed-opennodes.EncapTransitDecapCPNFail-OpenReacti
7、on:AtSourceKeepusingtheconfirmedflowsonEncapfailed-opennodes.Sincethesourcecannotbeupdated,controllerneedstomaintaintheexistingEncapTransitDecaptunnels.CPNDetectionandRecoveryUp→Fail-Open●Nocontrolplaneconnection:○OpenFlowco
此文档下载收益归作者所有