Active Queue Management (AQM) Based on Proportional Integral Controller Enhanced PIE) for Data-Over-Cable Service Interface Specifications (DOCSIS) Cable Modems
RFC 8034
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Type |
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RFC - Informational
(February 2017; No errata)
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Last updated |
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2017-02-28
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Replaces |
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draft-white-aqm-docsis-pie
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IETF
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plain text
pdf
html
bibtex
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Reviews |
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WG state
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Submitted to IESG for Publication
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Document shepherd |
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Wesley Eddy
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Shepherd write-up |
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Show
(last changed 2016-02-16)
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IESG state |
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RFC 8034 (Informational)
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Consensus Boilerplate |
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Yes
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Telechat date |
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Responsible AD |
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Martin Stiemerling
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Send notices to |
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"Wesley Eddy" <wes@mti-systems.com>
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IANA review state |
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IANA OK - No Actions Needed
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IANA action state |
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No IC
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Internet Engineering Task Force (IETF) G. White
Request for Comments: 8034 CableLabs
Category: Informational R. Pan
ISSN: 2070-1721 Cisco Systems
February 2017
Active Queue Management (AQM) Based on
Proportional Integral Controller Enhanced (PIE) for
Data-Over-Cable Service Interface Specifications (DOCSIS) Cable Modems
Abstract
Cable modems based on Data-Over-Cable Service Interface
Specifications (DOCSIS) provide broadband Internet access to over one
hundred million users worldwide. In some cases, the cable modem
connection is the bottleneck (lowest speed) link between the customer
and the Internet. As a result, the impact of buffering and
bufferbloat in the cable modem can have a significant effect on user
experience. The CableLabs DOCSIS 3.1 specification introduces
requirements for cable modems to support an Active Queue Management
(AQM) algorithm that is intended to alleviate the impact that
buffering has on latency-sensitive traffic, while preserving bulk
throughput performance. In addition, the CableLabs DOCSIS 3.0
specifications have also been amended to contain similar
requirements. This document describes the requirements on AQM that
apply to DOCSIS equipment, including a description of the
"DOCSIS-PIE" algorithm that is required on DOCSIS 3.1 cable modems.
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/rfc8034.
White & Pan Informational [Page 1]
RFC 8034 PIE-Based AQM for DOCSIS Cable Modems February 2017
Copyright Notice
Copyright (c) 2017 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. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Overview of DOCSIS AQM Requirements . . . . . . . . . . . . . 3
3. The DOCSIS MAC Layer and Service Flows . . . . . . . . . . . 4
4. DOCSIS-PIE vs. PIE . . . . . . . . . . . . . . . . . . . . . 5
4.1. Latency Target . . . . . . . . . . . . . . . . . . . . . 5
4.2. Departure Rate Estimation . . . . . . . . . . . . . . . . 6
4.3. Enhanced Burst Protection . . . . . . . . . . . . . . . . 7
4.4. Expanded Auto-Tuning Range . . . . . . . . . . . . . . . 7
4.5. Trigger for Exponential Decay . . . . . . . . . . . . . . 8
4.6. Drop Probability Scaling . . . . . . . . . . . . . . . . 8
4.7. Support for Explicit Congestion Notification . . . . . . 8
5. Implementation Guidance . . . . . . . . . . . . . . . . . . . 9
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
7.1. Normative References . . . . . . . . . . . . . . . . . . 10
7.2. Informative References . . . . . . . . . . . . . . . . . 10
Appendix A. DOCSIS-PIE Algorithm Definition . . . . . . . . . . 11
A.1. DOCSIS-PIE AQM Constants and Variables . . . . . . . . . 11
A.1.1. Configuration Parameters . . . . . . . . . . . . . . 11
A.1.2. Constant Values . . . . . . . . . . . . . . . . . . . 11
A.1.3. Variables . . . . . . . . . . . . . . . . . . . . . . 12
A.1.4. Public/System Functions . . . . . . . . . . . . . . . 12
A.2. DOCSIS-PIE AQM Control Path . . . . . . . . . . . . . . . 13
A.3. DOCSIS-PIE AQM Data Path . . . . . . . . . . . . . . . . 15
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