Byte and Packet Congestion Notification
draft-ietf-tsvwg-byte-pkt-congest-11
| The information below is for an old version of the document |
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Type |
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Active Internet-Draft (tsvwg WG)
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Last updated |
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2013-10-24
(latest revision 2013-08-01)
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Replaces |
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draft-briscoe-tsvwg-byte-pkt-mark
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Stream |
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IETF
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Intended RFC status |
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Best Current Practice
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Formats |
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plain text
pdf
html
bibtex
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WG state
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WG Document
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Document shepherd |
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Gorry Fairhurst
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Shepherd write-up |
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Show
(last changed 2013-08-28)
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| IESG |
IESG state |
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Approved-announcement to be sent::Point Raised - writeup needed
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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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tsvwg-chairs@tools.ietf.org, draft-ietf-tsvwg-byte-pkt-congest@tools.ietf.org
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| IANA |
IANA review state |
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IANA OK - No Actions Needed
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IANA action state |
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None
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Transport Area Working Group B. Briscoe
Internet-Draft BT
Updates: 2309 (if approved) J. Manner
Intended status: BCP Aalto University
Expires: February 2, 2014 August 1, 2013
Byte and Packet Congestion Notification
draft-ietf-tsvwg-byte-pkt-congest-11
Abstract
This document provides recommendations of best current practice for
dropping or marking packets using any active queue management (AQM)
algorithm, including random early detection (RED), BLUE, pre-
congestion notification (PCN) and newer schemes such as CoDel and
PIE. We give three strong recommendations: (1) packet size should be
taken into account when transports detect and respond to congestion
indications, (2) packet size should not be taken into account when
network equipment creates congestion signals (marking, dropping), and
therefore (3) in the specific case of RED, the byte-mode packet drop
variant that drops fewer small packets should not be used. This memo
updates RFC 2309 to deprecate deliberate preferential treatment of
small packets in AQM algorithms.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on February 2, 2014.
Copyright Notice
Copyright (c) 2013 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
Briscoe & Manner Expires February 2, 2014 [Page 1]
Internet-Draft Byte and Packet Congestion Notification August 2013
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.
Briscoe & Manner Expires February 2, 2014 [Page 2]
Internet-Draft Byte and Packet Congestion Notification August 2013
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Terminology and Scoping . . . . . . . . . . . . . . . . . 6
1.2. Example Comparing Packet-Mode Drop and Byte-Mode Drop . . 7
2. Recommendations . . . . . . . . . . . . . . . . . . . . . . . 9
2.1. Recommendation on Queue Measurement . . . . . . . . . . . 9
2.2. Recommendation on Encoding Congestion Notification . . . . 10
2.3. Recommendation on Responding to Congestion . . . . . . . . 11
2.4. Recommendation on Handling Congestion Indications when
Splitting or Merging Packets . . . . . . . . . . . . . . . 12
3. Motivating Arguments . . . . . . . . . . . . . . . . . . . . . 12
3.1. Avoiding Perverse Incentives to (Ab)use Smaller Packets . 12
3.2. Small != Control . . . . . . . . . . . . . . . . . . . . . 14
3.3. Transport-Independent Network . . . . . . . . . . . . . . 14
3.4. Partial Deployment of AQM . . . . . . . . . . . . . . . . 15
3.5. Implementation Efficiency . . . . . . . . . . . . . . . . 17
4. A Survey and Critique of Past Advice . . . . . . . . . . . . . 17
4.1. Congestion Measurement Advice . . . . . . . . . . . . . . 17
4.1.1. Fixed Size Packet Buffers . . . . . . . . . . . . . . 18
4.1.2. Congestion Measurement without a Queue . . . . . . . . 19
4.2. Congestion Notification Advice . . . . . . . . . . . . . . 20
4.2.1. Network Bias when Encoding . . . . . . . . . . . . . . 20
4.2.2. Transport Bias when Decoding . . . . . . . . . . . . . 21
4.2.3. Making Transports Robust against Control Packet
Losses . . . . . . . . . . . . . . . . . . . . . . . . 23
4.2.4. Congestion Notification: Summary of Conflicting
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