Understanding the Impact of Network Impairments Over Internet-Based Telemedicine Video Traffic

The Internet is designed to provide best effort service, which is not suitable for real-time applications. Therefore, carrying real-time applications over the Internet presents a number of challenges. While quality of service technologies can overcome some of these challenges, most medical facilities and patient homes do not utilize them since there is a high cost associated. Telemedicine and related technologies provide a promising opportunity to improve our healthcare reach to wider populations. The low cost and ubiquity of the Internet can help deliver healthcare to a wider population. However, the unreliable connection properties of packet-based systems hamper the quality of Internet-based telemedicine applications. This research is aimed to explore the delay, jitter, and drop cutoff points for Internet-based videoconferencing applications where video quality stays above the acceptable peak-signal-to-noise-ratio value (25dB). An experimental study is conducted on our testbed where behavior of the Internet is emulated on a Linux PC using NIST Net, a network emulation tool. Video file utilized during these experiments is an ophthalmology telemedicine session and it was obtained from the Regenstrief Institute for Health Care. Video quality measurements are computed using Video Quality Metric (VQM) software, which was developed by the Institute for Telecommunication Sciences (ITS). Our analysis and results indicate that jitter has a severe effect on the video quality whereas the effect of delay is almost invisible. Drop effects are similar to jitter with less impact on video quality. Results presented in this paper include the cutoff points for these variables as well