How to Achieve PSTN Scalability and Reliability

Transcription

1 VoIP Services: Winning Strategies How to Achieve PSTN Scalability and Reliability Carsten Rossenhoevel Managing Director (EANTC AG)

2 About EANTC The European Advanced Networking Test Center offers vendor independent network quality assurance since EANTC, Berlin, Germany 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

3 U.S. VoIP service provider outage in August 2004: 90 mins failure Small number of subscribers affected Reduces service quality to 99.98% - still quite good

4 Consequences of a Failure VoIP carrier services are under observation Technical press, analysts 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!

5 Definition Internet voice solutions: Voice over IP service offered by a full-service operator (controlling the last mile and Internet access to the VoIP soft switch and border gateways) Net Centrex full-service solution (all the above, plus a virtual PBX) Internet telephony service offered by an application service provider (controlling only the VoIP soft switch and border gateways) Peer-to-peer Internet telephony

6 Risk Analysis We identify six main groups of potential risks for a VoIP carrier service: Scalability Availability Speech Quality Management and Accounting Warranty Claims These risks can be managed by careful proof of concept and acceptance testing

7 Scalability Testing VoIP networks grow fast Residential networks may reach millions, business networks 10,000s of customers Growth is not linear: High call volume at New Year s Eve New customers added in a short time following marketing activities Many voice boxes in use during holiday season Emulate any future traffic conditions with call generators to ensure scalability Anzahl Anrufe (in Tausend) Unexpected Call Load

8 Scalability Testing ( 2 ) Untested software often doesn t scale Example: Customer growth can slow down operational speed of databases, interfaces, etc. disproportionally Generic vendor tests do not substitute carrier tests because specific configurations often scale differently Hardware Investment System Performance Verify scalability of all call types and situations

9 Availability Testing Any service component will fail eventually Many fatal outages are caused by erroneous switch-over procedures Network behavior can only be predicted with realistic proof of concept tests under load Pure functionality tests are not representative at all! Emulate failure of all components and services, eliminate single points of failure

10 Speech Quality Customers should "feel" VoIP call quality to be similar or better than PSTN Components: Network jitter Packet loss CODEC quality Echo cancellation MOS ISDN GSM G.723/9 Severe Impairment G711 Network quality measurements and automated MOS tests help to assess subjective call quality

11 Don t Forget Management Management plane needs to keep up with network growth Customer self-service provisioning interfaces are subject to peak loads Fault monitoring needs to scale to many subscribers (alert errors with short delay) 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 improves legal position in case of accounting tests

12 Warranty Claims Carrier equipment is typically used 3-5 years Warranty periods are often only 6-12 months Full scale not reached within warranty period Lack of scalability can t be claimed in time 100% Careful acceptance tests anticipating the max. With acceptance tests without scalability help to raise flaws within warranty period, saving money Scale 1 Time 5 yrs

13 Summary A well-performing service is a mandatory prerequisite for a successful paid VoIP carrier service Network reliability and maintenance of service levels will be one of the main differentiating factor for VoIP service providers Serious proof of concept and acceptance tests can improve VoIP scalability and reliability considerably

14 Thank you for your interest! For further information, please contact us: EANTC AG Einsteinufer 17 D Berlin Germany Phone: Fax: