Towards Intent -based Networking: A High-level Northbound ... · •Well defined south-bound interface, e.g. OpenFlow •Not much progress on north-bound interface (NBI) •State-of-the-art

ETSINEW INTERNET FORUM

12 October 2018

TowardsIntent-basedNetworking:AHigh-levelNorthboundInterfaceforSDN

Marinos Charalambides (UniversityCollegeLondon)

© ETSI 2018 - All rights reserved

ETSI New Internet Forum

BACKGROUNDANDMOTIVATION



NetworkResourceConfiguration(1/2)

3

• Resourceconfigurationobjectives• Meetrequirementsofofferedservices,e.g.delayguarantees• Meet(internal)operatorrequirements,e.g.security,energyconsumption• Effectiveandefficientuseofinfrastructureresources

• Configurationcomplexity• Widerangeofserviceswithvaryingrequirements• Richsetofresourcesinnumbersandtypes(connectivity,storage,processing)• Largesetofconfigurationparameters• Fluidityofvirtualisedinfrastructures



NetworkResourceConfiguration(2/2)

4

• BusinessobjectivesHigh-levelrequirementsNetworkconfiguration• Manualprocessesmostly• Networkmanagementsolutions• NetConf,SNMP,proprietaryCLIs,OpenFlow• Low-levelconfigurationscriptsneeded

• Limitations• Timeconsuming – lackofautomation• Errorprone – configurationinconsistencies



Intent-Based Networking

5

• “Don’ttellmewhattodo;tellmewhatyouwant”• Connectivityserviceexample:forwardtrafficfromnodeAtonodeBwithdelay<20ms• Translationofrequirementstoconfigurationcommands

• ManagementofSoftware-definedinfrastructures• Welldefinedsouth-boundinterface,e.g.OpenFlow• Notmuchprogressonnorth-boundinterface(NBI)

• State-of-the-art• ONFandvendors:basicpropertiesandstructureofNBI• Rootsinpolicy-basedmanagement


High-level requirements

Management / Control Functionality

Network Elements

NB interface

SB interface


Benefits andChallenges

6

• AutomatingrequirementsdecompositionthroughaNBIcan:• Simplifyconfigurationprocessandavoidconfigurationinconsistencies• Allowfrequentchangestohigh-levelrequirements• Facilitatefasterservicedeployment

• Mainchallenge:rightabstractionstoassociaterequirementstomanagementfunctions,resources andcommodities

• Connectivityserviceexample• Resources:end-pointswitches• Commodity:traffic• Managementfunctions:pathcomputation,pathselection

©ETSI 2018 - All rights reserved

AN4

10ms 20ms

10ms

10ms 10msB


DECOMPOSINGHIGH-LEVELREQUIREMENTS



FutureNetworkRequirements

8

• Commonabstractionsto:• Exposeproperties/attributesofmanagementfunctionsandservices• Representresourcesandcommodities• Specifyandparsehigh-levelrequirements

• Definition/implementationofnorth-boundinterface• Maphigh-levelrequirementstonetworkmanagementfunctions• Currentlyinimmaturestate



SystemArchitecture

9

Mapstoavailableservicesandappropriatemanagementfunctions(commonabstr.model)


Enforcesconfigurations

Computesnewresourceconfigurations


High-levelRequirementsStructure

10

• Expressedinageneralformat• Predicate:actionstoexecute,e.g.forward,store,process• Commodity:commodityregulatedbyactions,e.g.traffic,videocontent• Target:networkresourcesinvolved,e.g.switch,server• Constraint:constraintsonactions,e.g.delay• Condition:conditionsonactionapplicability,e.g.valueofcommodity

• ConnectivityserviceexamplePredicate ForwardCommodity TrafficTarget ResourceA->ResourceBConstraint Delaylowerthan20msCondition Trafficfromclient1



ServiceMapping(1/2)

11

• High-levelrequirements<-->attributesofavailableservices• Serviceattributescapturedintemplates(servicedescriptors):• Operation(OP):basicfunctionalityrequiredtoprovidetheservice• InfrastructureRequirements(IR):whatisneededintheinfrastructureforthe

servicetooperate


Servicename Connectivity

OP Forward

IR CORS

TrafficSwitch;Link

TS CORSCST

AlltrafficResourceA->ResourceBDelay<20ms

PAF delay_connectivity

• TechnicalSpecifications(TS):specificationsonwhichtheservicemustbeoperated

• PerformanceAffectingFactors(PAF):dominatingfactorsaffectingtheperformance


ServiceMapping(2/2)

12

• Resolver:determinesdescriptormatchingtherequirementpredicate==operation

• Instantiator:updatesTechnicalSpecificationsfields(CO,RS,CST)



ManagementFunctionMapping(1/2)

13

• Managementfunctiondescriptors:• Commodities(CO):typeofcommoditiesregulatedbythefunction• Resources(RS):typeofresourcesconfiguredbythefunction• Function(FCT):operationsperformedbythefunctiononresourcesandcommodities


Functionname PathSelection

CO Traffic

RS Switch;Link

FCT Allocate(end_points,delay_constraint)

OPE delay_connectivity

• OperationEffects(OPE):performancefactorsaffectedbythefunctiondecisions


ManagementFunctionMapping(2/2)

14

• Resolver:determinesfunctiondescriptormatchingtheselectedservicefunctionCO==serviceCO& functionRS==serviceRS& OPE==PAF

• Selector:selectsbestsetoffunctionsaccordingtoknowledgebase



USECASESANDEVALUATIONRESULTS



Implementation

16

• Mininetfortopology,hostsandswitches• RESTAPItointerfacenetworkmanagementsystemtomininet• SmallsetofPOXcontrollerAPIsforthesouth-boundinterface• JSONforhigh-levelrequirementsanddescriptors• Iperftoemulatefixed-rateUDPclienttraffic



UseCase1:ConnectivityServicewithDelayConstraints

17



UseCase2:TrafficRedirectionthroughSecurityVNF

18



Conclusions

19

• North-boundinterfaceforSDNofparamountimportance• Needforrightabstractionlevelandinterfaceimplementation• Solutiondevelopedislightweightandfast• Time-complexityconstantwiththenumberofservicesandfunctions• Futurework• Experimentwithrealistictopologies• Competingrequirements• Feedbackfromnetworkmanagementsystemtomappingmechanism



Acknowledgement

DaphneTuncer,Gioacchino Tangari,GeorgePavlou

Thankyou

Questions?


Documents

Towards Intent -based Networking: A High-level Northbound ... · •Well defined south-bound interface, e.g. OpenFlow •Not much progress on north-bound interface (NBI) •State-of-the-art