VoIP Services: Winning Strategies How to Achieve PSTN

European Advanced Networking Test Center

VoIP Services: Winning Strategies

How to AchievePSTN Scalability and Reliability

Carsten RossenhoevelManaging Director

European Advanced Networking Test Center (EANTC AG)


About EANTC

§ Test and certification of network components for manufacturers

§ Proof of concept evaluation,acceptance tests and network design consultancy for service providers and large enterprises

§ Research and development of test methods and analysis tools

EANTC, Berlin, Germany

The European Advanced Networking Test Center offers vendor independent network quality assurance since 1991.


U.S. VoIP service provider outage in August 2004:

Ø 90 mins failure

Ø Small number of subscribers affected

Ø Reduces service quality to 99.98% - still quite good


Consequences of a FailureVoIP carrier services are under observation

Ø Technical press, analysts

Ø Customer blogs

Small outages can quickly lead to huge brand damages, specifically for established carriers:

VoIP service providers need to focus high quality service maybe even more than PSTN carriers!


DefinitionInternet voice solutions:Ø Voice over IP service offered by a full-service

operator (controlling the last mile and Internet access to the VoIP soft switch and bordergateways)

Ø Net Centrex full-service solution (all the above, plus a virtual PBX)

Ø Internet telephony service offered by an application service provider (controlling only the VoIP soft switch and border gateways)

Ø Peer-to-peer Internet telephony


Risk AnalysisWe identify six main groups of

potential risks for a VoIP carrier service:Ø Scalability

Ø Availability

Ø Speech Quality

Ø Management and Accounting

ØWarranty Claims

These risks can be managed by careful proof of concept and acceptance testing


Scalability TestingVoIP networks grow fast

Ø Residential networks may reach millions, business networks 10,000s of customers

Growth is not linear:Ø High call volume at

New Year‘s EveØ New customers added

in a short time following marketing activities

Ø Many voice boxes in use during holiday season

Emulate any future traffic conditions with call generators to ensure scalability

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UnexpectedCall Load


Scalability Testing (2)Untested software often doesn‘t scale

Ø Example: Customer growth can slow down operational speed of databases, interfaces, etc. disproportionally

Ø Generic vendor tests do not substitutecarrier tests becausespecific configurationsoften scale differently

Verify scalability of all call types and situations

Hardware Investment System Performance


Availability TestingAny service component will fail eventually

Ø Many fatal outages are caused by erroneous switch-over procedures

Ø Network behavior can onlybe predicted with realisticproof of concept tests under load

Ø Pure functionality tests are not representative at all!

Emulate failure of all components and services, eliminate single points of failure


Speech Quality

Customers should "feel" VoIP call quality to be similar or better than PSTN

Components:Ø Network jitter

Ø Packet loss

Ø CODEC quality

Ø Echo cancellation

Network quality measurements and automated MOS tests help to assess subjective call quality

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GSM

SevereImpairment

ISDN G711

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Don‘t Forget ManagementManagement plane needs to keep up with network

growthØ Customer self-service provisioning interfaces are subject

to peak loadsØ Fault monitoring needs to scale to many subscribers

(alert errors with short delay)Ø Accounting must report correct call usage under any

conditions (otherwise not all calls are charged, or claims can be expected if too much is charged)

Include all system interfaces in scalability tests, including the management plane – even improveslegal position in case of accounting tests


Warranty ClaimsCarrier equipment is typically used 3-5 yearsWarranty periods are often only 6-12 months

Ø Full scale not reached within warranty period

Ø Lack of scalability can‘t be claimed in time

Careful acceptance tests anticipating the max. scalability help to raise flaws within warranty period, saving money

100%

Sca

le

Time1 5 yrs

With acceptance tests… without


SummaryØ A well-performing service is a mandatory

prerequisite for a successful paid VoIP carrier service

Ø Network reliability and maintenance of service levels will be one of the main differentiating factor for VoIP service providers

Ø Serious proof of concept and acceptance tests can improve VoIP scalability and reliability considerably


Thank you for your interest!

For further information, please contact us:

EANTC AG Einsteinufer 17 D-10587 BerlinGermany

Phone: +49.30.318 05 95-0Fax: +49.30.318 05 95-10E-mail: [email protected]

www.eantc.de

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VoIP Services: Winning Strategies How to Achieve PSTN