Congestion avoidance and control
SIGCOMM '88 Symposium proceedings on Communications architectures and protocols
An adaptive congestion control scheme for real-time packet video transport
SIGCOMM '93 Conference proceedings on Communications architectures, protocols and applications
Promoting the use of end-to-end congestion control in the Internet
IEEE/ACM Transactions on Networking (TON)
Sharp or smooth?: comparing the effects of quantization vs. frame rate for streamed video
Proceedings of the SIGCHI Conference on Human Factors in Computing Systems
Designing DCCP: congestion control without reliability
Proceedings of the 2006 conference on Applications, technologies, architectures, and protocols for computer communications
Quantifying Skype user satisfaction
Proceedings of the 2006 conference on Applications, technologies, architectures, and protocols for computer communications
Analysis of Skype VoIP traffic in UMTS: End-to-end QoS and QoE measurements
Computer Networks: The International Journal of Computer and Telecommunications Networking
An Experimental Investigation of the Congestion Control Used by Skype VoIP
WWIC '07 Proceedings of the 5th international conference on Wired/Wireless Internet Communications
IEEE Transactions on Circuits and Systems for Video Technology
Video telephony for end-consumers: measurement study of Google+, iChat, and Skype
Proceedings of the 2012 ACM conference on Internet measurement conference
Experimental investigation of the google congestion control for real-time flows
Proceedings of the 2013 ACM SIGCOMM workshop on Future human-centric multimedia networking
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The Internet is facing a significant evolution from being a delivery network for static content to an efficient platform for multimedia content delivery. Well-known examples of applications driving this evolution are YouTube Video on Demand, Skype Audio/Video conference, IPTV and P2P video distribution. While YouTube streams videos using the Transmission Control Protocol (TCP), time-sensitive applications, such as Skype Audio/Video conference, employ the UDP because they can tolerate small loss percentages but not delays due to TCP recovery of lost packets via retransmissions. Since, differently from the TCP, the UDP does not implement congestion control, these applications must implement congestion control at the application layer in order to avoid congestion and preserve network stability. In this paper we investigate Skype Video congestion control in order to assess to what extent this application is able to throttle its sending rate to match the unpredictable Internet bandwidth while preserving resource for co-existing best-effort TCP traffic. We have found that: (1) Skype Video adapts its sending rate by varying frame rate, frame quality and video resolution; (2) in many scenarios a Skype Video call refrains from fully utilizing all available bandwidth thus not sending videos at the highest possible quality; (3) Skype Video employs an adaptive FEC action that is proportional to the experienced loss rate; (4) the sending rate matches a changing available bandwidth with a transient time as large as a hundred of seconds; (5) the minimum bandwidth required for a video call is 40kbps at 5 frames per second.