Profiling Skype video calls: Rate control and video quality
- 1 March 2012
- conference paper
- Published by Institute of Electrical and Electronics Engineers (IEEE)
Abstract
Video telephony has recently gained its momentum and is widely adopted by end-consumers. But there have been very few studies on the network impacts of video calls and the user Quality-of-Experience (QoE) under different network conditions. In this paper, we study the rate control and video quality of Skype video calls. We first measure the behaviors of Skype video calls on a controlled network testbed. By varying packet loss rate, propagation delay and bandwidth, we observe how Skype adjusts its rates, FEC redundancy and video quality. We find that Skype is robust against mild packet losses and propagation delays, and can efficiently utilize the available network bandwidth. We also find that Skype employs an overly aggressive FEC protection strategy. Based on the measurement results, we develop rate control model, FEC model, and video quality model for Skype. Extrapolating from the models, we conduct numerical analysis to study the network impacts of Skype. We demonstrate that user back-offs upon quality degradation serve as an effective user-level rate control scheme. We also show that Skype video calls are indeed TCP-friendly and respond to congestion quickly when the network is overloaded.Keywords
This publication has 11 references indexed in Scilit:
- Could Skype be more satisfying? a QoE-centric study of the FEC mechanism in an internet-scale VoIP systemIEEE Network, 2010
- Tuning Skype's Redundancy Control Algorithm for User SatisfactionPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2009
- Tracking Down Skype TrafficPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2008
- QRP08-1: Opinion Model for Estimating Video Quality of Videophone ServicesIEEE Globecom 2006, 2006
- Quantifying Skype user satisfactionACM SIGCOMM Computer Communication Review, 2006
- An Analysis of the Skype Peer-to-Peer Internet Telephony ProtocolPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2006
- On the TCP-Friendliness of VoIP TrafficPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2006
- Locating internet bottlenecksPublished by Association for Computing Machinery (ACM) ,2004
- Promoting the use of end-to-end congestion control in the InternetIEEE/ACM Transactions on Networking, 1999
- Mean Packet Queueing Delay in a Buffered Two-User CSMA/CD SystemIEEE Transactions on Communications, 1985