Characterization Guidelines for Active Queue Management (AQM)
RFC 7928
Internet Engineering Task Force (IETF) N. Kuhn, Ed.
Request for Comments: 7928 CNES, Telecom Bretagne
Category: Informational P. Natarajan, Ed.
ISSN: 2070-1721 Cisco Systems
N. Khademi, Ed.
University of Oslo
D. Ros
Simula Research Laboratory AS
July 2016
Characterization Guidelines for Active Queue Management (AQM)
Abstract
Unmanaged large buffers in today's networks have given rise to a slew
of performance issues. These performance issues can be addressed by
some form of Active Queue Management (AQM) mechanism, optionally in
combination with a packet-scheduling scheme such as fair queuing.
This document describes various criteria for performing
characterizations of AQM schemes that can be used in lab testing
during development, prior to deployment.
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 7841.
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/rfc7928.
Kuhn, et al. Informational [Page 1]
RFC 7928 AQM Characterization Guidelines July 2016
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Reducing the Latency and Maximizing the Goodput . . . . . 5
1.2. Goals of This Document . . . . . . . . . . . . . . . . . 5
1.3. Requirements Language . . . . . . . . . . . . . . . . . . 6
1.4. Glossary . . . . . . . . . . . . . . . . . . . . . . . . 7
2. End-to-End Metrics . . . . . . . . . . . . . . . . . . . . . 7
2.1. Flow Completion Time . . . . . . . . . . . . . . . . . . 8
2.2. Flow Startup Time . . . . . . . . . . . . . . . . . . . . 8
2.3. Packet Loss . . . . . . . . . . . . . . . . . . . . . . . 9
2.4. Packet Loss Synchronization . . . . . . . . . . . . . . . 9
2.5. Goodput . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.6. Latency and Jitter . . . . . . . . . . . . . . . . . . . 11
2.7. Discussion on the Trade-Off between Latency and Goodput . 11
3. Generic Setup for Evaluations . . . . . . . . . . . . . . . . 12
3.1. Topology and Notations . . . . . . . . . . . . . . . . . 12
3.2. Buffer Size . . . . . . . . . . . . . . . . . . . . . . . 14
3.3. Congestion Controls . . . . . . . . . . . . . . . . . . . 14
4. Methodology, Metrics, AQM Comparisons, Packet Sizes,
Scheduling, and ECN . . . . . . . . . . . . . . . . . . . . . 14
4.1. Methodology . . . . . . . . . . . . . . . . . . . . . . . 14
4.2. Comments on Metrics Measurement . . . . . . . . . . . . . 15
4.3. Comparing AQM Schemes . . . . . . . . . . . . . . . . . . 15
4.3.1. Performance Comparison . . . . . . . . . . . . . . . 15
4.3.2. Deployment Comparison . . . . . . . . . . . . . . . . 16
4.4. Packet Sizes and Congestion Notification . . . . . . . . 16
4.5. Interaction with ECN . . . . . . . . . . . . . . . . . . 17
4.6. Interaction with Scheduling . . . . . . . . . . . . . . . 17
5. Transport Protocols . . . . . . . . . . . . . . . . . . . . . 18
5.1. TCP-Friendly Sender . . . . . . . . . . . . . . . . . . . 19
5.1.1. TCP-Friendly Sender with the Same Initial Congestion
Window . . . . . . . . . . . . . . . . . . . . . . . 19
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