Green VoIP : A SIP Based Approach

Abstract: This master thesis presents, examines, designs, implements, and evaluates with respect to energy efficiency a secure and robust VoIP system. This system utilizes a Session Initiation Protocol (SIP) infrastructure assisted by a cloud service, specifically focusing on small to medium sized enterprises (SME) and homes. This research focuses on using inexpensive, flexible, commodity embedded hardware (specifically a Linksys WRT54GL wireless router for the local site with a customized operating system, specifically DD-WRT). The idea is to reduce the local site's power consumption to very low levels by examining which functions can be done in a cloud service rather than at the local site. The thesis presents the design of a low-power IP telephony system for the local site and the cloud site. A number of different usage scenarios and desirable features are described. The methodology for conducting a set of experiments is defined to perform stress-testing and to evaluate the low- power IP telephony system's design. The experiments concern the overall power consumption of the local site under various configurations, the VPN link's call capacity, the QoS metrics for the VoIP calls, the session request delay (SRD) and the registration request delay (RRD). The results from these experiments show that there is a potential for significant power savings when using the proposed design for an IP telephony system.