Eclipse: A New Dynamic Delay-based Congestion Control Algorithm for Background Traffic

Initially, the Internet transport protocol TCP has been designed to provide a "best effort" service: it is meant to share the network resources with other users and applications. However, there is nowadays also a growing demand for transmitting big amounts of data in the background, namely background transport that uses spare capacity, but with minimal effect on other traffic. For instance, systems can proactively download content that the user/system would need in the future (e.g. update packages, video files, etc.). Efforts have therefore been made in the IETF for the sake of such a service with Low Extra Delay Background Traffic (LEDBAT) congestion control. While LEDBAT works in some cases, there are however known situations where it causes serious performance problems, particularly in combination with the ubiquitous bufferbloat for example in current broadband networks. In this paper, we analyse the issues of LEDBAT and propose a new approach for background traffic. Inspired by an astronomical event, we have named this approach Eclipse. Unlike LEDBAT, Eclipse can dynamically adapt to the network characteristics not only to minimise the additional network delay but also to maximise the utilisation of spare network capacity. We will show the usefulness of Eclipse by simulations.