A VoIP Path Decision-Making System with Forecast and Feedback Mechanisms in Multi-path Envi-ronment

• Main Authors: Chia-Li Chang, 張家力
• Other Authors: 高勝助
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/31698043306507778726

碩士 === 國立中興大學 === 資訊科學與工程學系所 === 101 === In this thesis, we propose a VoIP optimal route selection method. Based on mul-ti-path routing techniques, Session Initiation Protocol, and Real Time Protocol, our method effectively solves the drawback of ASs(autonomous systems) which fails to select routes based on quality. Our method has two important mechanisms: a forecast of optimal routes before a route decision is made and an analysis and feedback of op-timal routes after the route decision. To forecast optimal routes, our method analyzes the packet delay, packet loss, and comprehensive voice transmission quality assess-ment values between VoIP servers and clients based on the AS-Path and IP address information from internet service providers. In the optimal route analysis and feedback after a route selection decision has been made, we compute comprehensive voice transmission quality assessment values by sampling packets from voice calls in session. We compare the computed assessment value and the predicted assessment value before the route selection decision was made. A greater assessment value indi-cates a better voice quality which likely is associated with smaller packet delay and packet loss rates. Our experimental studies show that VoIP services with multiple routes provide better service quality than those with single routes. Our method improves the voice quality by up to 15.2%, since it assigns optimal routes to VoIP users compared to traditional methods which assign worse routes.