Less-than-Best-Effort Service: A Survey of End-to-End Approaches

This paper provides a survey of transport protocols and congestion control mechanisms that are designed to have a smaller bandwidth and/or delay impact on standard TCP than standard TCP itself when they share a bottleneck with it. Such protocols and mechanisms provide what is sometimes called a less-than-best-effort or lower than best-effort service. To a user, such a service can, for instance, be an attractive choice for applications which create traffic that is considered less urgent than that of others-e.g., automatic backup, software updates running in the background, or peer-to-peer applications. The focus of this survey is on end-host approaches for achieving a less-than-best-effort service. This includes e.g. upper-layer methods, or techniques that leverage standard transport-layer mechanisms so as to reduce the impact on other competing flows.