Ensuring Quality in

the Contact CenterJoseph DumontProduct ManagerContact Center ServicesEmpirix, Inc.

Abstract: This presentation will focus on assuring IP telephony voice quality in the contact center and the enterprise. The presenters will address concepts such as active call monitoring and multilayer monitoring, and discuss how these strategies can be used to determine when a failure has occurred or is about to occur in an IP telephony network. The conversation will include a discussion of how performance management reporting can be used to assure that service level objectives are met and how recurring failures can be identified and prevented in real-time.

Proactive multi-channel testing and monitoring of contact center and communication solutions and their role in improving performance and customer experience will also be addressed. This is a shared session with IQ Services. You will each have time for a 20 minute presentation, with a 5 minute Q&A at the end.

• How do I know I have a problem?– Is the voice quality on my

network acceptable?– Is everything working

properly?

• What’s wrong &how do I fix it?– Is increased traffic

effecting voice quality?

– Is something broken? What is it?

– Did something change that effects voice quality?

– How do I get to the source of the problem?

• How do I detect trends and know when my next problem will occur?

– Are things trending toward degrading quality?

– Do I have recurring problems? Every Monday morning? Some other event?

Assuring IPT Voice Quality

LifecycleAssurance

Initial Baseline New

BusinessInitiatives

(ie: CTI,

Speech Rec)

Identifying a Problem

What Could Possibly Go Wrong?User• Acoustic echo; handset speaker to microphone• Hybrid echo; impedance mismatching (handset or local loop)• Distortion; hybrid analog-to-digital conversion and compression

Network• Network faults• Over capacity• Circuit noise; switching• External noise; crosstalk • Signaling protocol mis-matches• Transcoding; compression• Echo suppression• Delay (Latency); packet, speech• Jitter; packet, speech• Out of order packets• Loss of packets• Duplicate packets

IPT Infrastructure Management

ManagementSystem

UC App Servers

http access

SNMP Monitoring

CDRs/CMRs

Backend Systems

Gateway Stats

VVVV

PSTN

Troubleshooting

Troubleshooting

Passive MonitoringWhat is it?

• Insert Network Probe– Locate probes around the network– Probes “listen” to all calls and report call quality

• Solution types– Protocol Analyzers– VoIP specific monitoring probes

Pros• See “real” calls, trace

problems to specific endpoints

• Possible to monitor every call

• Reactive - must wait for a “bad” call to detect a problem

• Difficult troubleshooting - hard to determine what caused the problem

• Expensive – need lots of probes to cover large networks

Cons

Active MonitoringWhat is it?

• Place monitoring calls and measure call statistics– On and off the network

Pros• Simulates a real call,

follows actual call path• Accurate measurements• Proactive – detect

problems early• Extensive testing, IVRs,

CTI, etc.

• Cannot see every call• Takes resources

Bandwidth Directory Numbers

Cons

Infrastructure MonitoringWhat is it?

• Collect call statistics from switches and gateways– CDRs, CMRs– Phone Stats– RTCP collectors

Pros• Inexpensive• Collect information as seen

by the infrastructure – consistent reporting

• Reactive - must wait for calls to all locations

• Difficult to determine what caused the problem

• Limited diagnostic capabilities

Cons

TroubleshootingWhat do I need to test and

monitor?• Infrastructure– Switch / Media Gateway handoffs– Media Gateway echo insertion / loss– Agent “Presence” or registrations– Voice quality over WAN / Toll-bypass links– Conference Bridge Link Voice Quality

• Application– IP IVR embedded CTI– Speech Voice activity detection (VAD) impact on

Speech enabled applications– DTMF Acceptance parameters

(In-band vs. Out-of-band signaling)

Performance Management

Performance ReportingWhat Are the Trends?

• Voice quality getting worse?• Recurring problems?• Poor VQ correlated with other factors?

Summary• Identify a problem– Passive Monitoring– Active Monitoring

• Troubleshoot to find the cause of the problem

• Performance management– Find trends– Identify trouble periods

Supplementary Slides

Ways to Detect Problems

• Users complain• Customers

complain• CEO complains

Much Better

Not Good

• Test before deployment• Passive monitoring• Gather information

from the infrastructure• Active monitoring

Measuring Voice Quality

• Specified by ITU-T P.830 in 1996

• Range of results: 1 to 5• Absolute Category

Rating (ACR) is: 5 is excellent

4 is good

3 is fair

2 is poor

1 is bad

Mean Opinion Score (MOS)

• Individuals provide an ACR score

• Resultant MOS is an average of the scores

Panel of Human Listeners

• Expensive to set up• Cumbersome maintenance• Inconsistent results• Not practical or scalable

for live networks or frequent regression testing

Problems

MOS = (3+4+3+5)/4 = 3.75

IP Voice QualityFactors Impacting Quality

Gateway Gateway/Phone

Lost Packets

CODEC-introduces some distortion

Jitter

Late packets are discardedby jitter buffer

Round trip delay

Passive, Non-reference-Based E-model

Gateway Gateway/Phone

Lost PacketsCODEC-introduces some distortion

Jitter

Late packets are discardedby jitter buffer

Round trip delay

E-model

R Factor

Active, Reference-basedPESQ

FFT FFT

Perceptually weightedObjective score

Test (speech) fileSent thru’ network

500 MIPS processor

PESQ algorithm (ITU P.862) based on and replacesprevious (ITU P.861 PSQM, BT PAMS) algorithms

VoIPService

VoiceQualityTester