MTA Loopback VoIP Testing

Identify Network Issues Before Your Customers Start to Complain

With Tektronix’ MTA loopback testing, Cable MSOs can remotely test tomultimedia terminal adapters (MTAs) to monitor and troubleshoot VoIP servicequality as perceived by their subscribers. No field test equipment is required.

Tektronix’ unique test method uses softswitch integration to activate the Voiceor RTP loopback test mode in any PacketCable™ 1.x (and above) compliantMTA from suppliers such as Motorola, Arris, and Scientific Atlanta. With over 50VoIP QoS measurements, operators can quickly identify service quality issuesusing advanced, standards-based algorithms, while detecting DTMFtransparency and call connectivity problems.

The Speech & DTMF Loopback Test Agent uses the MTA as an RTP packetreflector to assess media transmission performance over the HFC or VoIPnetwork to the subscriber’s premises.

The audio loopback feature tests the MTA’s internal circuitry (including thecodec) to evaluate the true user-perceived speech-quality, including theimpairments caused by the codec’s D/A & A/D speech conversion andcompression.

� True user-perceived speechquality (MOS, R-factor) testedover an actual DQoS voice-priority channel

� Complete VoIP qualityassessment including callvolume, noise, distortion,clipping, DTMF transparencyand call connectivityperformance

� Industry-unique softswitchintegration for fully NCScompliant loopback testing thatkeeps the CMS in sync withsubscriber status during testing

� Reference-qualitymeasurements that allows forbenchmarking of competingtechnologies and services

Features & Benefits Applications

Datasheet | www.tektronix.com/ActiveAssurance

Reduce Truck Rolls Through Remote Fault Isolation withthe Speech & DTMF Loopback Test Agent

� Measures key call-quality metricssuch as MOS, Clipping, DTMFtransparency, and Noise

� Evaluate codec performance

� Enables market-wide quality reporting

� Launch calls from both PRI and MGCPinterfaces

� Remotely isolate inside wiring issuesto lower opex

� Hub to edge QoE testing without fieldtest equipment

� Long-term monitoring and pro-activefault detection

� Remote fault isolation reduces truckrolls

� Verify subscriber connectivityunobtrusively before and after networkmodifications

Loopback MGCP LQ listening quality Dual Tone Multi-Frequency DTMF Voice over IP Mean Opinion Score time divisionmultiplex PP500 PP6000 quality of experience quality of service Real-time Transport Protocol primary rate interface SessionInitiation Protocol Media Gateway Control Protocol Perceptual Evaluation of Speech Quality Voice Quality Evaluation Systemshort message system responder probe Operations Operational Support Systems internet protocol receive signal level

2

Datasheet | MTA Loopback VoIP Testing

Network Architecture for MTA Loopback VoIP Testing

DirectQuality Web-BasedOSS: This servercentralizes test planswith predefined Pass/Failcriteria, stores results,and offers advancedreporting & trending.

Integrates easily withexisting OSSs withGatewayDQ™.

PowerProbe 6000 orPowerProbe 500 runsthe Speech and DTMFLoopback Test Agent byplacing test calls toMTAs throughout yournetwork, to measuremore than 50 metrics.

IP ManagementTraffic

NetworkCore

Summary View of Test Results From DirectQuality’s web-based OSS

eMTA

HFC - RFCoaxialCable

RTP Loopback

Voice Loopback

Codec

True Voice-Path Testing

Tektronix’ MTA loopback testsconduct measurements of true user-perceived service quality. This allowsyou to identify and resolve problemsbefore your subscribers know aboutthem.

Softswitch Integration

Tektronix’ patent-pending MTAloopback technique is fully integratedwith Call Management Servers (CMS /Softswitches) to reserve and activatePacketCable voice-priority DynamicQuality of Service (DQoS) channels forloopback test calls. This ensures thatthe CMS always has the correctsubscriber / network status.

Competing MTA-loopback techniquesbypass the CMS and cannot properlyestablish voice-level priority inPacketCable networks as CableModem Termination Systems (CMTS)ignore non-DQoS traffic prioritizationschemes including IP ToS/DiffServand VLAN tags. This leaves the switch

desynchronized with the subscriber’sstatus.

Tektronix MTA loopback testing willnot interfere with residential phoneservice availability: We comply withPacketCable specifications to ensurea call is never interrupted, and that adial-tone is always available.

Network Fault Isolation with theRTP Loopback Test Agent

Cable MSOs can remotely isolatedistribution network faults that occurbetween the fibernode and the MTAby performing a loopback test to thetransponder with our RTP LoopbackTest Agent as shown below.

Isolate distribution networkfaults by performing RTPloopback to theTransponder with the RTPLoopback Test Agent

Fibernode

Fault Isolation

3www.tektronix.com/ActiveAssurance

SSppeeeecchh QQuuaalliittyyPESQ LQ MOSVQES MOSThe MOS measures speech quality in terms ofend-user perception using a scale from 1(worst) to 5 (best)

Unsatisfied Users RatioSpeech Power, Loss & Distortion

NNooiisseeC-Message NoiseWideband NoiseNoise GainC-Notch Noise Gain Signal-To-Noise Ratio

VVooiiccee TTrraannssmmiissssiioonnJitter & Jitter Buffer UsagePacket Loss & TransmissionPacket Discard & Out-of-OrderBurst Density & DurationGap Density & DurationFrame Muting RatioComfort NoiseClipping Events (Front-End, Back-End, & In-Between)

Clipping Ratio (Front-End, Back-End, & In-Between)

Average Clipping Duration (Front-End,Back-End, & In-Between)

Hang-Over EventsAverage Hang-Over TimeDetect speech clipping problems caused byVoice Activity Detectors (VADs) using Front-End and Back-End Clipping measurements, and analyze the impact of silence suppressionby measuring Hangover events.

DDeellaayyRound-Trip Delay

FFrreeqquueennccyy RReessppoonnsseeLoss (1100 Hz, 2100 Hz)RSL (1100 Hz, 2100 Hz)

DDTTMMFF DDeetteeccttiioonn && VVaalliiddaattiioonnVerify a network’s ability to transmit DTMF(Touch) Tones.

0 to 9, *, #

FFaaxx TToonnee DDeetteeccttiioonnTest Fax-over-IP tone transmissionperformance to ensure codecs supportcontinuous Fax frequencies.

CNG Tone Detection & DurationCED Tone Detection & Duration

NNeettwwoorrkk TTiimmeerrssDial Tone DelayPost Dial DelayBilling DurationCall Duration

CCoonnnneeccttiioonn SSttaattuussCall Disposition CodePRI Cause Number & LocationMGCP Return CodeComplete Call Progress Analysis is performedfor each test call according to Tektronix’sexclusive Enhanced E.180 algorithm.

NOTE: Test measurement availability varies according tothe network protocol the PowerProbe is used with.

Create Reports by origin, destination, city, region, or breakout for any testing period fornetwork monitoring, troubleshooting, and trending

In the QoS Analysis View, User-Defined Service Level Classes are Usedto Present Results in Highly-Identifiable Pass / Fail Categories

Characteristics

Contact Tektronix:

Please visit www.tektronix.com/communications

Phone:1-800-833-9200 option 1+1-469-330-4000

Locate your nearest Tektronix representative at:www.tektronix.com/contactus

Copyright © Tektronix. All rights reserved. Tektronix products are covered by U.S. and foreign patents, issued andpending. Information in this publication supersedes that in all previously published material. Specification and pricechange privileges reserved. TEKTRONIX and TEK are registered trademarks of Tektronix, Inc. All other trade namesreferenced are the service marks, trademarks or registered trademarks of their respective companies. All screen imagesare simulated.

09/08 | CCW-20528-2

For Further Information:

Tektronix maintains a comprehensive, constantlyexpanding collection of application notes, technicalbriefs and other resources to help engineers working on the cutting edge of technology.

Please visit www.tektronix.com/communications

About Tektronix:

Tektronix Communications provides network operatorsand equipment manufacturers around the world anunparalleled suite of network diagnostics and management solutions for fixed, mobile, IP andconverged multi-service networks.

This comprehensive set of solutions support arange of architectures and applications such asLTE, fixed mobile convergence, IMS, broadbandwireless access, WiMAX, VoIP and triple play, including IPTV.

Benchmark Competing Technologies with Industry-StandardSpeech Quality Algorithms

The Speech and DTMF agent incorporates standards-based VQES and PESQalgorithms that provide quality measurements that are ideal for thebenchmarking of competing technologies and services.

VQES Algorithm

Monitors the end-to-end quality of your voice services using MCI Labs’statistics-based Voice Quality Evaluation System (VQES) algorithm. It calculatesVQES MOS and Unsatisfied User Ratio, as well as conducting a fullconnectivity performance analysis.

PESQ Algorithm

Assesses the end-to-end quality of voice services using the ITU-T PESQalgorithm, to implement the PESQ Listening Quality MOS, frame muting forpacket-loss detection, distortion, and voice clipping.

TDM / IP Interface Testing

Unique to the industry, Tektronix’ PowerProbes can conduct loopback testsfrom the PSTN-side of media gateways. This permits full assessment of theeffects PSTN/IP conversion has on VoIP quality while verifying the subscriber-experience when receiving off-net calls from outside the cable operator’snetwork.

DirectQuality Web-Based OSS

Advanced Test Automation

DirectQuality anticipates measurement requirements and will generate andexecute testing plans based on your QoS objectives. Automate test plans orstart tests on-demand.

Color-Coded Service Levels

DirectQuality simplifies the monitoring of service faults by displaying resultsusing user-definable Service Level Classes. Service violations can be forwardedto fault management systems via SNMP.

Business-level QoS Reports

DirectQuality provides a set of business-driven report templates with high-leveland drill-down views.

Datasheet | MTA Loopback VoIP Testing