Charge-based low priority congestion control

With the best-effort TCP transporting foreground traffic, below-best-effort transport protocols are developed to transport background traffic. However, we argue in this paper that: 1) two fixed levels of priority are not enough, and 2) the background and foreground transfers are subjective concepts which can only be decided by users but not arbitrarily determined by the network according to the application type of the traffic. Then we propose the charge-based low priority congestion control (TCP-CBLP), an algorithm not only provide multiple flexible priority levels lower than best-effort TCP, but also helps users allocating their available bandwidths effectively to optimize their utilities. Simulation results show that the algorithm is fair, stable, and can optimize userspsila utilities.