Application flow control in YouTube video streams

This paper presents the results of an investigation into the application flow control technique utilised by YouTube. We reveal and describe the basic properties of YouTube application flow control, which we term block sending, and show that it is widely used by YouTube servers. We also examine how the block sending algorithm interacts with the flow control provided by TCP and reveal that the block sending approach was responsible for over 40% of packet loss events in YouTube flows in a residential DSL dataset and the retransmission of over 1% of all YouTube data sent after the application flow control began. We conclude by suggesting that changing YouTube block sending to be less bursty would improve the performance and reduce the bandwidth usage of YouTube video streams. Categories and Subject Descriptors C.2.0 [Computer Communications Networks]: General General Terms Measurement, Performance Keywords YouTube, Flow Control, Block Sending, Packet Loss, DSL

• Type: Journal
• Year: 2011
• Where: CCR
• Authors: Shane Alcock, Richard Nelson
• Keywords: Application flow Control, CCR 2011, Packet Loss, Software Engineering, YouTube