Carrier Ethernet Educational Series Chap 3 Ang

Service Turn-Up

Carrier Ethernet Basics Educational Series 4 5 61 32

AUTHORS

BRUNO GIGUÈRE, Advisor–CTO Office, EXFOSYLVAIN CORNAY, Marketing Manager, EXFOHAMMADOUN DICKO, Product Specialist, EXFOTHIERNO DIALLO, Product Specialist, EXFOSOPHIE LEGAULT, Product Line Manager, EXFOSUE JUDGE, Consultant

EXFO Inc.August, 2011

Service Turn-Up

3– 3

3. WHAT IS SERVICE TURN-UP FOR CARRIER ETHERNET? . . . . . . . . . . . . . . . . . . . . . . . . . 3– 4

3.1 Ethernet Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3– 5

3.1.1 Business Services . . . . . . . . . . . . . . . . . . . . . . . . .3– 6

3.1.2 Mobile Backhaul Services . . . . . . . . . . . . . . . . . . . . .3– 7

3.2 Test Architectures and Modes . . . . . . . . . . . . . . . . . . . . . . .3– 8

3.2.1 Test Architecture . . . . . . . . . . . . . . . . . . . . . . . . . .3– 8

3.2.1.1 Distributed Test Architecture . . . . . . . . . . . . . . . . . . . 3– 8

3.2.1.2 Centralized Test Architecture . . . . . . . . . . . . . . . . . . . 3– 9

3.2.1.3 Testing Using Network Interface Devices. . . . . . . . . . . . 3– 9

3.2.1.4 Performance End-Point Unit. . . . . . . . . . . . . . . . . . . 3– 10

3.2.2 Test Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3– 10

3.2.2.1 Testing to a Loopback Function . . . . . . . . . . . . . . . . 3– 10

3.2.2.2 Testing a Dual Test-Set Scenario . . . . . . . . . . . . . . . . 3– 10

3.3 Service Turn-Up Test Methodologies . . . . . . . . . . . . . . . . . . 3– 12

3.3.1 ITU-T Y.1564 Ethernet Service Activation Test Methodology 3– 12

3.3.1.1 ITU-T Y.1564 Service Configuration Test. . . . . . . . . . . . 3– 12

3.3.1.2 ITU-T Y.1564 Service Performance Test . . . . . . . . . . . . 3– 14

3.4 Birth Certificate 16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3– 15

3.5 Sample Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3– 16

3.5.1 Business Ethernet Services . . . . . . . . . . . . . . . . . . 3– 16

3.5.1.1 Service Configuration Test. . . . . . . . . . . . . . . . . . . . 3– 16

3.5.1.2 Service Performance test . . . . . . . . . . . . . . . . . . . . 3– 17

3.5.2 Mobile Backhaul Services . . . . . . . . . . . . . . . . . . . . 3– 17

3.5.3 Synchronization. . . . . . . . . . . . . . . . . . . . . . . . . . 3– 18

Also coming soon to the Carrier Ethernet Basic Educational Series, modules that will focus on the following aspects of Carrier Ethernet, including service monitoring and troubleshooting.

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WHAT IS SERVICE TURN-UP FOR CARRIER ETHERNET?3

Four phases are essential to building, characterizing and evaluating a Carrier Ethernet network: construction, service turn-up/burn-in, monitoring and troubleshooting. The service turn-up and burn-in phase is critical as it proves that the circuit can deliver the performance as specified in the service level agreement (SLA), which is the last phase for service providers to qualify the network before delivery to the customer.

•Characterizephysicalconnections

•Validatelinkperformance

•Ensurecleanconnections

•Performwire-speedservicevalidationthrough EtherSAM testing (ITU-T Y.156sam) or RFC 2544

•Validateproperserviceconfi guration/provisioning (i.e.,VLANandclassofservice)

•Defineaconsistentprocedureto activate services quickly and effi ciently

•Archivetestresultsforreportingandfuture referencing purposes

•24x7measurementsofkeyperformanceindicators(KPIs)fordeployedservices

•MetricsgatheredviaOAM-compliantEthernet devices (IEEE 802.1ag and ITU-TY.1731)

•Alerts/alarmstoreportservicedegradations and initiate the service troubleshooting process

•AggregationandanalysisofKPIsforhistorical and near real-time reports

•Servicedegradationtroubleshooting triggered by performance monitoring system

•TestsfromtheMSCtothetower, leveraging Ethernet OAMstandardstotestandinterrogate remote devices

•Dispatchtechnicianwithportable device to perform additional troubleshooting

SERVICE MONITORING

SERVICE TROUBLESHOOTINGCONSTRUCTION SERVICE

MONITORINGSERVICE TURN-UP AND BURN-IN 4

Figure 3.1 The service lifecycle assessment

The turn-up and burn-in cycle is a dual-stage process where carriers and service providers test and validate their service confi guration and the provisioning of the different classes of service (CoS) in the network. The key aspect of the service turn-up phase is validating that the network elements are properly confi gured and that the network is able to support the different services while ensuring their performance.

Theburn-inphasefocusesonalongertestperiod,typically24to72hours,withthegoalofevaluating how the network reacts when all the services are forwarded at the same time and attheirmaximumcommittedrate.Duringthesetwophases,thekeyperformanceindicators(KPIs)aremonitoredtoensurethatperformanceismetatalltimes.

Thefollowingsectionsfocusonserviceturn-up.WewillreviewthemainKPIsrelatedto business and mobile backhaul services and present the different test architectures, modes and methodologies available to validate services.

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Service Turn-Up

3.1 Ethernet ServicesThe main Metro Ethernet Forum (MEF) technical specifications covering Ethernet services are:

• MEF 10.2:TheEthernetServiceAttributes (Phase2)definesKPIserviceattributes

• MEF 23:CarrierEthernetClassofServiceImplementationAgreement(Phase1)provides a CoS framework that can be used by service providers to define the performanceexpectationsofdifferentservices.

When combined, these MEF specifications provide the definition required to assesstheperformanceofEthernetservices.However,guidanceonKPIs iscurrently limited, especially for Ethernet services. As the MEF is working to address this issue, service providers have to rely on best practices or turn to otherrecommendationsinthemeantime,suchastheITU-TY.1541(NetworkPerformanceObjectivesforIP-BasedServices),publishedinFebruary2006toprovideguidanceonKPIsfordifferentservices.

CoS Label

EVC Type

FD FDV FLR Ingress UNI Bandwidth

Profile Constraints 3

PCP / PHB (DSCP)CoS and Color Identifiers 1

PCP / PHB (DSCP)

CoS-only Identifiers 1

Example Applications

Color Green Color

Yellow 2

w/DEI

HPt-Pt AFD AFDV AFLR CIR>0

EIR3≥04

CF=0

5 / EF (46)

N/Sin phase 1

5 / EF (46) VoIPandbackhaul controlMulti-pt AFD AFDV AFLR

MPt-Pt BFD BFDV BFLR CIR>0

EIR3≥03/AF31

(26)2/AF32(28)orAF33(30)

2-3/AF31-33(26,28,30)

Nearreal-time or critical

data appsMulti-pt BFD BFDV BFLR

LPt-Pt CFD CFDV CFLR

CIR3≥0EIR3≥0 5

1 / AF11 (10)

0 / AF12 (12), AF13(14)or

default (0)

0-1/AF11-13(10, 12, 14) or default (0)

TBDinfuturephaseMulti-pt CFD CFDV CFLR

Figure 3.2 Three class-of-service, MEF model (MEF 23 Table 2)

Asdescribeinfigure3.2,themainKPIsusedforEthernetservicesareframedelay(FD),framedelayvariation(FDV)andframelossratio(FLR).AlthoughMEF23isbeing revisited to include values not currently defined, we can still use the table asareferencetoolforthedifferentservices.Oneattributethatisnotcurrentlycovered in the turn-up phase of the Ethernet services lifecycle is availability. As it is a long-term variable (measured over months to a year’s period), we will not address it in Ethernet services turn-up but rather in the Service-Monitoring chapter.

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Carrier Ethernet Basics Educational Series 1 2 4 5 63

3.1.1 Business Services

Whether an Ethernet service provider or mobile backhaul service provider, all operators face a number of similar challenges: They need to optimize the quality of service (QoS) and reduce operational costs, while managing their network life cycleeffectively.Theyarerequiredtodelivermoreandmorecomplexsolutionsinareduced amount of time. Any service turn-up solution will need not only to validate all their SLA parameters but also to take into account these challenges. The service activation methodology ITU-T Y.1564 is the only one that addresses today’s realities.

Whenitcomestobusinessservices,thereisabroadrangeofavailableKPIstochoose from, depending on the application(s) being delivered and the geographic rangeof theservice.Forexample,ametroservicewillnothavethesameFDconstraints as a long-haul service.

Network Performance Parameter

Nature of Network Performance Objectives

QoS Classes

Class 0

Class 1

Class 2

Class 3

Class 4

Class 5 Unspecified

IPTD Upper bound on themeanIPTD

100 ms 400 ms 100 ms 400 ms 1 s U

IPDV Upper bound onthe1x10-3 quantile of IPTDminustheminimumIPTD

50 ms 50 ms U U U U

IPLR Upper bound on the packet loss probability

1x10-3 1x10-3 1x10-3 1x10-3 1x10-3 1x10-3

IPER Upper bound 1x10-4 U

Table 1 – Example of KPIs for IP services based on ITU-T Y.1541

Table1providesanupperlimitforthedifferentKPIsincludedinITU-TY.1541.TheIPpackettransferdelay(IPTD),IPpacketdelayvariation(IPDV),IPpacketlossratio(IPLR)andIPpacketerrorratio(IPER)parameterscanbeleveragedtoprovide guidance for the Ethernet service attributes that need to be validated.

From a best-practice perspective, the following KPI values are commonlyacceptedforbesteffort(lowpriority)services:FDof5msto30ms,FDVof2to10 ms and FLR of 10-6.

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Service Turn-Up

3.1.2 Mobile Backhaul Services

WithitshighbandwidthandlowFD,FDVandFLRrequirements,mobilebackhaulserviceshavethemoststringentSLAofallservices.Figure3.3demonstratestheevolution of mobile backhaul services requirements from an SLA and bandwidth requirement perspective.

GSM(assuming that the primary service is voice)

WCDMA(assuming that the primary services are voice and best-effort mobile broadband connectivity)

LTE(assuming that the primary services are video (on-demand, P2P), gaming, VoIP and best-effort mobile broadband)

One-waydelay Max:40msTarget: 10 ms

Max:30msTarget: 10 ms


Delayvariation Max:10msTarget: 5 ms


Max:2msTarget: 1 ms

Packetlossrate Max:10-3

Target: 10-4Max:10-3

Target: 10-6Max:10-3

Target: 10-6

Classes of service (Cos) 2 2 to 4 2to7

Availability 99.99 99.99 99.99

Typical backhaul per base station (Low:Med:High)

2:4:8 E1(2M) 6:20:50 Mbit/s 90:180:400+Mbit/s

Figure 3.3 Typical SLA for mobile backhaul networks

Anotherinterestingconceptbroughtforwardinfigure3.3istheCoSevolution.Through the evolution of technologies, the number of CoS evolved from two to a maximumofseven.AsEthernetmobilebackhaulservicesaremostlyusedfor3Gand4Gnetworks,wewillconcentrateonthesetechnologies.WhenitcomestoEthernet mobile backhaul services, the best guidance can be found in MEF 22 (MobileBackhaulImplementationAgreement-Phase1).Table2providesaviewofthe service attributes for a four CoS service.

Service Class Name Bandwidth Profile CoS Performance Objectives

FD FDV FLR

VeryHigh(H+) CIR>0EIR=0

AFD AFDV AFLR

High (H) CIR>0EIR=0

BFD BFDV BFLR

Medium (M) CIR>0EIR≥0

CFD CFDV CFLR

Low (L) CIR≥0EIR≥0*

DFD DFDV DFLR

Notes:A≤B≤C≤DandAFDV is as small as possible (*) both CIR = 0 and EIR = 0 is not allowed as this results in no conformant Service Frames

Table 2 – Service class model for mobile backhauling (MEF 22 – Table 2)

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Service Class Name

Example of Generic Traffic Classes Mapping into CoS

Four CoS Model Three CoS Model Two CoS Model

Veryhigh(H*) Synchronization – –

High (H) Conversational, Signaling and Control

Conversational, and Synchronization,

Signaling and Control

Conversational, and Synchronization,

Signaling and Control

Medium (M) Streaming media Streaming media –

Low (L) Interactive and Background

Interactive and Background

Interactive and Background

Table 3 – Examples of mobile backhaul traffic class mapping into four, three and two CoS models

Table3mapsdifferentmobileapplicationstoCoScategories,themostimportantof which (in a four CoS model) is the very high service class that is used for synchronization.Dependingonthewirelesstechnologyinuse,synchronizationranges from very important to crucial in the delivery of quality services. As already mentioned in previous chapters, there are two complementary technologies to deliverEthernet-basedsynchronization,PTP(IEEE1588v2)andsynchronousEthernet. As both have a high impact on network quality, they are covered more thoroughly in the Service Turn-Up Test Methodologiessection3.3.

3.2 Test Architectures and ModesTest architectures and modes are very important when it comes to Ethernet services turn-up and troubleshooting. Each architecture and mode has economical andtechnicaladvantagesandlimitations.Dependingonthegoalsoftheserviceprovider,amixoftestarchitecturesandmodescouldbebeneficialtodeliverandmaintain quality services.

3.2.1 Test Architecture

There are two test architectures that can be leveraged to provide Ethernet service turn-up:

• Distributedtestingusingportabletestinstrumentsconnectedtoeachtestpoint

• Centralizedtestheadplacedstrategicallyinthenetwork

3.2.1.1 Distributed Test Architecture

The portable test instrument scenario is the classic test architecture. This scenario isthemostexpensivetestarchitectureastwoportableinstrumentsaredeployedand operated simultaneously. This translates into two simultaneous truck rolls requiringcoordinationbetweenbothtestends.Onthepositiveside,thistestscenario provides the best test performance as both ends use specialized test equipment with complete and targeted test functionalities.

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Service Turn-Up

3.2.1.2 Centralized Test Architecture

Centralized test scenarios implement active testing via test appliances that are located at strategic locations throughout the network and then launching tests from these points to portable devices located at other test points. The centralized test unit can be installed in hard-to-reach places (such as central offi ce cabinets and remote locations) and are controlled remotely. This allows for test personnel and engineers to operate tests from virtually any location. In some cases, however, test personnel must be sent to the end points to complete testing. In such cases, portable equipment can be used by mobile testpersonneltoexecuteeitherend-to-endorloopbacktests.Insuchascenario,testingcan occur at any point in the network, customer site or remote location.

Figure3.4providesagraphicalexampleofacentralizedtestprobethatcanconnect to an end-device for testing purposes.

Figure 3.4 Centralized test architecture

3.2.1.3 Testing Using Network Interface Devices

Anetworkinterfacedevice(NID)isadevicethatprovidesthedemarcationbetweenthe service provider and the customer. In the Carrier Ethernet world, this device serves as the physical demarcation point providing the user-to-network interface (UNI).NIDsalsoprovidethetraffic-shaping,traffic-policingandbufferingfunctionsas part of the bandwidth profi le defi ned by the MEF.

NIDscanalsosupplytestfunctionssuchasloopbackcapabilitiesandsupportforIEEE802.1agandITU-TY.1731OAM.Inactivetestscenarios,thesedevicesareconfi gured and used as loopback devices. Testing can then occur from a centralized testpointtotheNIDloopbackfunctionorfromaportabletestdevicelocatedataspecifictestpointtotheNIDinloopback.Somenetworkelements(suchasCarrierEthernetswitchrouters)haveabuilt-inNIDfunctionthatallowthesameOAMandtestcapabilitiesasfoundindedicatedtestNIDs.Fromatestperspective,thereisnodifferenceintestingtoatestNIDortoaNID-enablednetworkelement.

Ideally,NIDsaredeployedatallhandoffpointsandprovidetestingbenefits.Theseinclude reduced truck rolls as test loopback functions can be activated remotely. SincetheNIDisalwayslocatedatthispoint,thereisnoneedtosendtestpersonnelto the test site with a loopback device. Another benefi t is simplifi ed and accelerated troubleshooting. A customer ticket can be assessed quickly by testing to this loopback point to locate the problem spot (i.e., verify if the issue is found from the test pointtotheNIDlocationorbetweentheNIDlocationandthecustomerequipment).

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3.2.1.4 Performance End-Point Unit

Aperformanceend-point(PEP)unitisacost-effectivetestdemarcationdevicethatgivesserviceprovidersremotevisibilityoftheirentirenetwork.ThePEPunit acts as a test responder to any Ethernet test equipment and/or Ethernet monitoringsystem.ThePEPunitcanbeusedthroughoutthenetworklife-cycle:turn-up, monitoring and troubleshooting.

AswithaNIDusedduringserviceturn-up,aPEPdeviceloopbacksthetesttrafficto a test instrument or probe, providing the test infrastructure required to perform differenttestswithoutbeingin-linewithtrafficasaNIDwould.

3.2.2 Test Modes

3.2.2.1 Testing to a Loopback Function

TheITU-TY.1564EthernetServiceActivationTestMethodologycanbeexecutedround-tripvia theuseofa loopbackdevice(aPEPunit for instance). In thiscase, the results reflect the effects of both test directions, from the test function to the loopback point and back to the test set. In such a scenario, the loopback functionality can be performed by another test instrument in Loopback mode or by aPEPdeviceinLoopbackmode.

3.2.2.2 Testing a Dual Test-Set Scenario

The ITU-T Y.1564 Ethernet Service Activation Test Methodology can also be run inDualTest-Setmode,asshowninChapter2.Inthisscenario,twotestsets,one designated as local and the other as remote, are used to communicate and independentlyruntestsperdirection;thisprovidessupplementarytestflexibility.

Results from both directions are sent and displayed on the local unit. This ensures that the entire test routine can be completed by a single person in control of both test instruments from a single unit, providing reduced test time and manpower. This flexibilityalsoensuresthatdifferentunitscanbesetastheremoteunit.Themostinteresting scenario is a test unit at a centralized point that is always configured asaremoteunit,configuredwithfixedaddresses.Thecarriercansimplydispatchasingletestpersontoatestsitetoquicklydiscoverandexecuteserviceturn-upandburn-inefficientlywithoutrequiringanextraworkerinthecentraloffice.

The dual test-set approach also provides the capability to segment the network and quickly pinpoint in which direction the issues occur. This is especially important in cases where bandwidth is different between the upstream and downstream direction. In such cases, using a loopback tool will always yield the same results since the measurement will be affected by the lowest throughput and the test results will not show that one direction has higher performances than the other. With the dual test-set approach, both directions are independently analyzed at the same time and pass/fail results are provided per direction.

InFigure3.5,thebandwidthis30Mbit/sinonedirectionand70Mbit/sintheother direction. Measuring the bandwidth in one direction will not be sufficient; therefore a bidirectional test is required.

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Service Turn-Up

Executingthetestinonedirectionatatimeisagoodtroubleshootingmethod;however, network elements behave differently when unidirectional test traffi c and bidirectionaltrafficisused.Inunidirectionaltrafficgeneration,theCPUofthenetwork element only processes traffi c in one direction, therefore using its full switchingcapabilitiestothisonedirection.InBidirectionalTrafficmode,theCPUisexercisedwithtesttrafficcomingfrombothdirections,reflectingthereal-worldenvironment. The bidirectional test methodology ensures that the circuit is fully stressed in both directions by ensuring that they are always tested at the same time. This is mandatory when assessing the performance of services during the turn-up phase.

Figure 3.5 Bidirectional Test Example

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3.3 Service Turn-Up Test MethodologiesThere are currently two standardized test methodologies used for service turn-up: RFC 2544 and ITU-T Y.1564.

As previously mentioned in section 2.1 of Chapter 2, RFC 2544 is the traditional methodology when it comes to service turn-up. Unfortunately, this methodology was created to assess the performance of network elements in a lab environment and not turn-up services in the field. As defined in the test methodology, RFC 2544 has drawbacks since it only validates part of the service attributes; it is very long to complete (the latency test duration is 4.66 hours on its own), and the testcoverageofthemethodologyisverylimited.Duetothefactthatwefindthatthis methodology is not well-suited to service turn-up, we will concentrate on our recommended standardized test methodology: ITU-T Y.1564.

3.3.1 ITU-T Y.1564 Ethernet Service Activation Test Methodology

Whether an Ethernet service provider or mobile backhaul service provider, all operators are faced with a number of challenges. They need to optimize QoS and reduce operational costs while managing their network life cycle effectively. They arechallengedtodelivermoreandmorecomplexsolutionsinareducedamountof time. Any service turn-up solution will need not only to validate all their SLA parameters but to also take into account those challenges. The service activation methodology ITU-T Y.1564 is the only one that addresses today’s realities. As previously mentioned in Chapter 2, there are two tests that make up ITU-T Y.1564:

• The service configuration test is a per-service test that measures and verifies bandwidth and performance requirements of a specific service as defined by the user. The process follows three key phases and monitors all performance indicators during these phases, ensuring that they are all met at the same time.

• The service performance test provides a snapshot of the performance of all deliveredservicesduringtheirnormalstateofoperation.Thenextsectionwillprovide more detailed information on each test.

3.3.1.1 ITU-T Y.1564 Service Configuration Test

There are three phases of testing to perform per service, meaning that if multiple servicesexiston thenetwork,eachserviceshouldbe testedoneata time. This ensures that there is no interference from other streams and that the bandwidth and performance of a specific service is being measured.

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Service Turn-Up

Phase 1: From Minimum to CIR

In this phase, bandwidth for a specifi c service is ramped up from a minimum data rate to the committed information rate (CIR). This phase ensures that the network is able to support this specifi c service at different data rates while maintaining performance levels. It also provides a safe and effective way to ramp up utilization without overloading a network in case the service is incorrectly confi gured.

The suggested ramp-up is by increments of 25%, starting at 25% of the CIR. The final step is testing at the CIR rate. This methodology ensures a quick assessment of the behavior of the network as the service is ramping up. For fi ner granularity,theramp-upcanbeadjustedtosmallervalues.Ifanyperformanceparameter or frame loss occurs, the test shall be declared as failed since the service requirements are not met.

• RX throughput = TX throughput• KPIs < Fail threshold

• RX throughput = TX throughput• KPIs > Fail threshold

Expected results:

√CIR

Figure 3.6 Minimum to CIR bandwidth ramp-up

Phase 2: Testing at CIR to CIR + EIR

Inthisphase,theserviceisramped-upfromtheCIRtotheexcessinformationrate(EIR). This step ensures that the service’s EIR is correctly confi gured and that the EIR rate can be attained. However, as by accepted principles, performance is not guaranteed in the EIR rates, therefore no performance assessment is performed at this stage. The focus of the test is essentially to ensure that the service can support EIR without any frame loss.

Expected results:

• RX throughput = TX throughput• KPIs not monitored

• RX throughput < CIR

√CIR

CIR + EIR

Figure 3.7 CIR to EIR bandwidth ramp-up

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Phase 3: Overshoot Testing

Oneoftheattributesofpackettransportisthecapabilitytohandleburstytraffic.Inconditionsofburst,overshootenvironmentsthatexceedtheEIRcanoccur,usually leading to discarded traffi c.

In this step, traffic is sent above the EIR and the receive rate is monitored. TheexpectedthroughputisessentiallytheEIRasanytrafficovertheEIRshouldbediscarded as red traffi c. If more traffi c than the EIR is received, this would indicate that a device is not properly confi gured and thus a fail condition shall be declared.

Expected results:

• RX throughput = EIR + CIR • KPIs not monitored,

• RX throughput > EIR + CIR or CIR

√CIR

CIR + EIR Discard

Figure 3.8 Overshoot testing

3.3.1.2 ITU-T Y.1564 Service Performance Test

While the service confi guration test focused on the proper confi guration of each service in a network element, the service performance test focuses on testing the actual service and the enforcement of the QoS parameters under CIR conditions.

In this test, all confi gured services are generated at the same time at CIR for a soakingperiodthatcanrangefromafewminutestodays.Duringthissoakingperiod, the performance of each service is individually monitored, and if any service fails to meet its performance parameters, a fail condition is declared.

• KPIs within SLA per service

• Any KPI fails

Service test pass/fail criteria:

√

CIR Service 3

CIR Service 2

CIR Service 1

Service 1

Service 2

Service 3

Figure 3.9 ITU-T Y.154 service performance sample test results

The combination of the service confi guration and performance tests provides critical results in a simple and complete test methodology. It quickly identifi es confi guration faults via the network confi guration tools by focusing on each service and how they are handled by the network elements along the paths. This test suite then focuses on the network capacity to handle and guarantee all the services simultaneously. Oncebothphasesarepassed,thecircuitisthenreadytobeactivatedandbeputin service.

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Service Turn-Up

3.4 Birth Certifi cateWhen the service turn-up and burn-in is complete, reports must be created in order to provide traceability and reference before the circuit is delivered to the customer or placed in service.

These reports may include the following:

• Physical test report: This collection of reports includes physical testing results(suchasOTDRtracesandlayer1BERtests)toprovethatthephysicalspecifi cation of the new circuit is met.

• Service turn-up report: This report proves that service handling has been correctly confi gured on the forwarding devices and that the performance meets the service activation criteria.

• Burn-in report: This report (based on the ITU-T Y.1564 methodology) provides performancedetailsforservicestestedforamediumperiod(from24to72hours).ThereportprovidesadescriptionoftheservicesandtheaverageandmaximumvaluesoftheKPImeasured.

The collection of these test reports is now the birth certifi cate of the circuit.

BIRTH CERTIFICATE

TURN-UP RESULTS BURN-IN RESULTS

Physical report: Burn-in results: Birth certifi cate:•Linkquality •Servicestesting •Completeperformance•Physicaltesting •End-to-endqualityassessment ofthecircuit

Service turn-up report:•Per-serviceperformance

Figure 3.10 Birth certifi cate components

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3.5 Sample ApplicationsThe ITU-T Y.1564 service activation methodology is recommended for business andmobilebackhaulservicesturnup.TheKPIsmeasuredarethesame(i.e.,bandwidth, frame loss ratio, frame transfer delay and inter-frame delay variation), however, the SLAs could vary. The following sections provide sample SLA configurations and turn-up testing scenarios.

3.5.1 Business Ethernet ServicesThefigurebelowshowsanexampleofanSLAforthreeservices:data,voiceand video. With ITU-T Y.1564, the administrator can configure three classes of service:data,voiceandvideo.EachservicehasitsownVLANaswell.AlltheSLAparameters need to be validated during the service turn-up phase.

Performance Attribute Data Voice Video

CIR (Mbit/s) (green traffic) 50 0.12 3.97

EIR (Mbit/s) (yellow traffic) 0 5 5

Frame delay (ms) <6 <15 <15

Frame delay variation (ms) <1 <2 <2

Frame loss (%) <0.001 <0.1 <0.1

VLAN 100 200 300

Figure 3.11 Sample business Ethernet SLA configuration

3.5.1.1 Service Configuration Test

In addition to defining the SLA requirements, the administrator could also choose the ramp-up steps. As suggested earlier, the steps can be set to 25% of the committedinformationrate(CIR).TheKPIswillbemeasuredforeachstepandeach service. The figure below shows the service configuration results of the exampleabove.

Step CIR (%) Frame Loss (%)

Max Jitter (ms)

Max Latency (ms)

Verdict Average Throughput (Mbit/s)

1 50.0 0.0 0.100 5.051 √ 1.988

2 75.0 0.0 0.098 5.051 √ 2.981

3 90.0 0.0 0.098 5.051 √ 3.577

CIR 100.0 0.0 0.098 5.051 √ 3.974

Overshoot 0.0 0.100 5.051 √ 4.002

Figure 3.12 Sample business Ethernet service configuration results

All the SLA parameters are met in this case; therefore, the network is configured properly and can allow traffic from all three services simultaneously.

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3.5.1.2 Service Performance test

Oncetheserviceconfigurationtestsarecompletedsuccessfully,thenextstepisto run a service performance test for all three services. In this phase, the SLA parameters will be measured for all services simultaneously. The administrator can choose to run a test for a short or long period (24 hours or even a few days) for a burn-intest.Belowaretheserviceperformanceresultsoftheexampleabove.

Service No.

Average Throughput

(Mbit/s)

Frame Loss (%)

Max Jitter (ms)

Max Latency (ms)

Verdict

1 50 0.0 0.262 5.179 √

2 0.125 0.0 0.296 5.175

3 3.972 0.0 0.259 5.051 √

Figure 3.13 Sample business Ethernet service performance results

The results obtained from the service configuration and service performance tests can be used to issue a birth certificate.

3.5.2 Mobile Backhaul ServicesDuring theservice turn-upphaseofmobilebackhaulservices,differentSLAparameters are validated depending on the type of wireless network technology used. The SLA below is one that can be used for an LTE network service turn-up. At least seven services need to be tested in this case. The administrator needs to set-upsevenclassesofservice.Justlikeinthepreviousexample,theadministratorcan use the ITU-T Y.1564 service configuration and service performance tests to validate the SLA parameters of all seven services.

LTE Traffic Transport Service Class PCP DSCP LTE Interface

Synchronization Synchronization 7 111xxx Sync

BearerOAM BearerOAM 4 100xxx OAM

QC | Level

1/2 Voice/linevideo 6 110xxx S1. X2

3 Voiceondemand 3 011xxx S1. X2

4 Real-time gaming 5 101xxx S1. X2

5 Control/management 7 111xxx S1. X2

6/7/8/9 Others 0,1,2 000xxx-010xxx S1. X2

Figure 3.14 Sample mobile Backhaul service SLA configuration

3– 18


One-Way Latency

OneimportantKPIthatismeasuredformobilebackhaulservicesisframedelay(latency). In most cases, the round-trip latency (i.e., the time required for traffi c to go across a network and back to the original point) is measured during turn-up. In Ethernet services the latency between two points is usually the same in both directions, therefore it is half of the round-trip delay.

Whendetermining the time,PTP IEEE1588v2assumesasymmetrical linkbetween the master and slave clocks. It is therefore important to measure the latency in each direction in order to make sure they are both the same. The one-way latency, which is the duration it takes traffi c from the master clock to the slave clock, needs to be measured in this scenario.

3.5.3 SynchronizationThe synchronization service turn-up and burn-in phase allows network engineers to qualify the ability of the network to properly service the synchronization traffi c according to its confi gured priority, and to verify the performance of the network synchronization fl ow under simulated or real-life loading conditions. As a service, typical testing should focus on the key performance indicators of frame delay variation, frame delay and frame loss and the infl uence of other streams on the synchronization stream during congestion or high network utilization conditions.

The burn-in phase is an essential testing phase where the fl ow is soaked for a longer test period to assess its stability under various load conditions. This phase provides an assessment of the stability of the network synchronization fl ow over a longer test period and provides a good indication of the capability of the network to effi ciently transport multiple services while maintaining the performance of the synchronization fl ow.

10 GigE

10 GigE

10 GigE

T1/E1

TDMFrequency

Data Center

T1/E1T1/E1T1/E1T1/E1T1/E1T1/E1

TDMTDMTDMTDMFrequency

T1

SSU

TDM

TDM Frequency

SyncE

TDMTDM

T1T1T1T1T1

10 GigE

10 GigESONET/SDH

GigE Metro

Core

TDM FrequencyTDM FrequencyTDM FrequencyTDM Frequency

TDMTDMFrequencyFrequencyFrequency

SyncWatch-110SyncWatch-110SyncWatch-110SyncWatch-110SyncWatch-110

SyncWatch-110

SyncWatch-110

IEEE1588v2

GigE

IEEE1588v2

IEEE 1588 andFrequency

SONET/SDH

SONET/SDH

CoreCore

GrandMaster (GM)

Figure 3.15 Sample Ethernet synchronization network

Documents

Carrier Ethernet Educational Series Chap 3 Ang