Open Research Issues in Internet Congestion Control
RFC 6077
Internet Research Task Force (IRTF) D. Papadimitriou, Ed.
Request for Comments: 6077 Alcatel-Lucent
Category: Informational M. Welzl
ISSN: 2070-1721 University of Oslo
M. Scharf
University of Stuttgart
B. Briscoe
BT & UCL
February 2011
Open Research Issues in Internet Congestion Control
Abstract
This document describes some of the open problems in Internet
congestion control that are known today. This includes several new
challenges that are becoming important as the network grows, as well
as some issues that have been known for many years. These challenges
are generally considered to be open research topics that may require
more study or application of innovative techniques before Internet-
scale solutions can be confidently engineered and deployed.
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 Research Task Force
(IRTF). The IRTF publishes the results of Internet-related research
and development activities. These results might not be suitable for
deployment. This RFC represents the consensus of the Internet
Congestion Control Research Group (ICCRG) of the Internet Research
Task Force (IRTF). Documents approved for publication by the IRSG
are not 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/rfc6077.
Papadimitriou, et al. Informational [Page 1]
RFC 6077 Open Issues in Internet Congestion Control February 2011
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document.
Papadimitriou, et al. Informational [Page 2]
RFC 6077 Open Issues in Internet Congestion Control February 2011
Table of Contents
1. Introduction ....................................................3
2. Global Challenges ...............................................5
2.1. Heterogeneity ..............................................5
2.2. Stability ..................................................7
2.3. Fairness ...................................................8
3. Detailed Challenges ............................................10
3.1. Challenge 1: Network Support ..............................10
3.1.1. Performance and Robustness .........................14
3.1.2. Granularity of Network Component Functions .........15
3.1.3. Information Acquisition ............................16
3.1.4. Feedback Signaling .................................17
3.2. Challenge 2: Corruption Loss ..............................17
3.3. Challenge 3: Packet Size ..................................19
3.4. Challenge 4: Flow Startup .................................24
3.5. Challenge 5: Multi-Domain Congestion Control ..............26
3.5.1. Multi-Domain Transport of Explicit
Congestion Notification ............................26
3.5.2. Multi-Domain Exchange of Topology or
Explicit Rate Information ..........................27
3.5.3. Multi-Domain Pseudowires ...........................28
3.6. Challenge 6: Precedence for Elastic Traffic ...............30
3.7. Challenge 7: Misbehaving Senders and Receivers ............31
3.8. Other Challenges ..........................................33
3.8.1. RTT Estimation .....................................33
3.8.2. Malfunctioning Devices .............................35
3.8.3. Dependence on RTT ..................................36
3.8.4. Congestion Control in Multi-Layered Networks .......36
3.8.5. Multipath End-to-End Congestion Control and
Traffic Engineering ................................37
3.8.6. ALGs and Middleboxes ...............................37
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