Voip

Network Test Solutions

Voice Over IP: Guaranteeing Carrier Grade Performance

©RADCOM Ltd., July 2002 Revision B

T

able of Contents
Introduction VoIP Architecture Test Strategy VoIP Testing Gateway Testing Gatekeeper Testing IVR Testing Billing & Pre-paid Testing NMS Testing Conclusion Appendix 1: List of Specifications Appendix 2: Glossary About RADCOM 1 3 4 6 13 16 19 21 22 22 2425 28

G

uaranteeing Carrier Grade Performance

Introduction
Voice over IP networks are complex. They represent the converging worlds of tele- and data communications, and therefore present myriad implementation and testing challenges: • Integration to traditional telecom infrastructure • Integration to billing systems • Many add-on services • Large variety of protocols • Quality is anissue • Network specialists are expensive and scarce • Reliability is a must • Multiple High Quality Services: voice, fax, video, unified messaging, call centers, etc. This white paper presents a typical VoIP architecture and then suggests a framework for testing VoIP networks. The test strategy is presented as well as a detailed discussion of the actual testing required for each network element.Finally, a list of Voice over IP specifications is provided as an appendix as well as a list of acronyms. The main objective of this paper is to provide insight into the intricacies of architecting Voice over IP networks of carrier grade quality. It is intended for network design and test engineers.

2

Currently, there is only one system in the market that allows full end to end testing andmapping of quality vs. stress. This is RADCOM's VoIP Performer™.

It introduces a new conceptual method for testing Voice over IP networks, as can be seen in Figure 1. The Performer™ includes high performance emulation and simulation components as well as powerful quality measurement and analysis components. The complete system is controlled from a single management console and allows scripting andautomating of the testing procedures. The following are the components of the Performer™: • QPro - multiple PSTN client emulation including objective quality measurements. • 323Sim - multiple H.323 client emulation including registration, signaling and media. • SIPSim - multiple SIP client emulation including registration, signaling and media. • NetSim - network cloud emulation includingintroduction of impairments.

Guaranteeing Carrier Grade Performance

3

• MediaPro - real time packet based objective and subjective quality measurements.

Figure 1: RADCOM's VoIP Performer™ introduces a new conceptual method for testing Voice over IP networks

VoIP Architecture
A typical VoIP network includes the following components: • Media gateways • Signaling gateways • Gatekeepers •Class 5 switches • SS7 network • Network management system • Billing systems

Guaranteeing Carrier Grade Performance

4

All of these network elements communicate with each other using a plethora of protocols, as can be seen in Figure 2. A detailed list of protocols and specifications can be seen in Appendix I.

Figure 2: Typical VoIP architecture

Test Strategy
Testing VoIP networks is atri-fold task: • Functionality verification • Standards compliance • Performance verification

Guaranteeing Carrier Grade Performance

5

A successful pre-deployment testing strategy must address each of these three facets:

Figure 3: Test Strategy

Changes such as software or hardware version upgrades can cause degradation in functionality, quality and performance. Therefore, it isvery important to repeat this test cycle after every change made to the VoIP network. With RADCOM's VoIP Performer™ engineers can prepare test scripts that include the type of testing that is applicable to their specific system. The use of these test scripts provides a cost effective means for performing degradation testing when new hardware or software revisions are tested. Manual testing can be...