A Survey of Lower-than-Best-Effort Transport Protocols

Abstract

This document provides a survey of transport protocols 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 could be used for delay-insensitive "background" traffic, as they provide what is sometimes called a "less than" (or "lower than") best-effort service. Status of This Memo This document is not an Internet Standards Track specification; it is published for informational purposes. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6297.

Characterization Guidelines for Active Queue Management (AQM)

“…o Less-than-Best-Effort (LBE) congestion controls: Per [RFC6297], an LBE service "results in smaller bandwidth and/or delay impact on standard TCP than standard TCP itself, when sharing a bottleneck with it." A base-line congestion control for this category is Low Extra Delay Background Transport (LEDBAT) [RFC6817].…”

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

“…Generally, LBE behavior can be achieved at the transport layer with a mechanism that resembles TCP but exhibits a 1 For this reason, LBE is sometimes referred to as a scavenger service. more cautious behavior, e.g.…”

“…We thank Padma Bhooma for allowing us to use his figures from [51], and all the people who have contributed to RFC 6297 [1]: Melissa Chavez and Yinxia Zhao for reference pointers, as well as Jari Arkko, Mayutan Arumaithurai, Dragana Damjanovic, Elwyn Davies, Wesley Eddy, Stephen Farrell, Mirja Kuehlewind, Tina Tsou and Rolf Winter for their comments and suggestions.…”

“…Besides, by both running for very long periods and opening Manuscript received 3 November 2011; revised 12 May 2012. A shorter version of this paper appeared as RFC 6297 [1].…”

“…TCP-based bulk transfer applications will tend to saturate the bottleneck buffer, inducing huge delays that render interactive applications unusable [2]. Latency-sensitive flows may thus benefit from some flows receiving a less-than-best-effort (LBE) service-that is, a service that allows to use only residual network resources 1 and aims at lowering the impact of the latter flows on the former. In other words, users could obtain a more appropriate network behavior (perceived as better overall performance) if an LBE service were used by some applications, as this would allow time-critical data transfers to access more of the available bandwidth when they need it.…”