practice

Doi: 10.1145/2380656.2380671

Article development led by queue.acm.org

A proposal to improve the performance
and availability of streaming video and other
time-sensitive media.
bY aiman eRbaD anD chaRLes “bucK” KRasic
sender-side
buffers and
the case for
multimedia
adaptation

the internet/WeB architectUre has developed to the point where it is common for the most popular sites to operate at a virtually unlimited scale, and many sites now cater to hundreds of millions of unique users. Performance and availability are generally essential to attract and sustain such user-bases. As such, the network and server infrastructure plays a critical role in the fierce competition for users. Web pages should load in tens to a few hundred milliseconds at most. Similarly, sites strive to maintain multiple nines availability targets—for example, a site should be available to users 99.999% of the time over a one-year period.

Such stringent standards, however, are in practice carefully constructed to exclude problematic content such as video streaming and interactive virtual environments. If sites counted vid-eo-streaming rebuffer events against their availability, their multiple nines availability would vanish in a poof. Yet, one could argue that a video rebuffer just at the moment of the winning goal in the World Cup is a form of unavailability just as severe as, say, a failure that causes a social-network user to repeat some steps in composing a post. The goal of this article is to propose methods for adaptive transport that are ultimately aimed at bringing the performance and availability of streaming video and other time-sensitive media in line with that of traditional Web content. To do so we have developed an enhanced transport called Paceline.