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____________________________ Alfredo Terzoli and Mosiuoa Tsietsi

Re-establishing and improving the experimental VoIP link with the University of Namibia: A Case Study. Ricky Ngandu g07n1084@campus.ru.ac.za. ____________________________ Alfredo Terzoli and Mosiuoa Tsietsi. Project Aim/Objective. Establish a fully working VoIP link between RU and UNAM.

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____________________________ Alfredo Terzoli and Mosiuoa Tsietsi

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  1. Re-establishing and improving the experimental VoIP link with the University of Namibia: A Case Study Ricky Ngandu g07n1084@campus.ru.ac.za ____________________________ Alfredo Terzoli and Mosiuoa Tsietsi Rhodes University - Department of Computer Science

  2. Project Aim/Objective • Establish a fully working VoIP link between RU and UNAM Rhodes University - Department of Computer Science

  3. Approach • Learn about asterisk and gain practical experience • Learn about traffic shaping and test traffic shaping techniques on a network test-bed • Learn about UNAM’s network and their ISP SLA • Deploy iLanga at UNAM • Implement traffic shaping • Test the solution Rhodes University - Department of Computer Science

  4. RU – UNAM VoIP Link Rhodes University - Department of Computer Science

  5. Live Network • RU has a 12 224 Kbps Internet connection • UNAM has a 1 024 Kbps Internet connection • During working hours there is a high rate of network congestion at UNAM Rhodes University - Department of Computer Science

  6. Network Test-bed • Build a network to emulate the existing live network between RU and UNAM • Test call quality under normal and congested conditions • Implement traffic shaping and test call quality under normal and congested conditions Rhodes University - Department of Computer Science

  7. Results • Iperf program was used to measure bandwidth and throughput • ManageEngine VQManager was used to analyse VoIP and network traffic • Call quality is calculated and rated by MOS (Mean Opinion Score). MOS is described in ITU P.800 • MOS rates are between 1 and 5. MOS above 4 are toll quality and those below 3.6 are not satisfactory Rhodes University - Department of Computer Science

  8. Results (cont.) Rhodes University - Department of Computer Science

  9. Results (cont.) Rhodes University - Department of Computer Science

  10. Deployment Challenges • Geographic separation makes it challenging to streamline VoIP deployment between UNAM and RU • UNAM uses a Telecom owned ISP and their bureaucracy has stalled deployment due to blocked VoIP ports • Low bandwidth was a major headache during installation and testing Rhodes University - Department of Computer Science

  11. Challenge Solutions • To resolve the technical and bureacracy surrounding VoIP we opted to use two test sites UNAM and Polytechnic of Namibia (PoN) • We opted for IAX over SIP to bridge the two PBXs. This is due to security restrictions, codec limitations and a NAT-ed network • Speex codec works best over IAX between the sites. Speex compresses between 2 – 44Kbps Rhodes University - Department of Computer Science

  12. Conclusion • Traffic shaping improves the quality of voice calls over congested networks • IAX is better to use over congested and NAT-ed networks for audio but not video because there has been a slow development for video handling • SIP is better to use for video but is difficult to run over NAT-ed networks Rhodes University - Department of Computer Science

  13. Future work Although SIP is more widely used than IAX, SIP does not handle NAT-ed networks well. • Develop clients and codecs that handle video over IAX • Improve SIP to handle NAT-ed networks better Rhodes University - Department of Computer Science

  14. Questions? Rhodes University - Department of Computer Science

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