Advice to link designers on link Automatic Repeat reQuest (ARQ)
RFC 3366
| Document | Type |
RFC - Best Current Practice
(September 2002; No errata)
Also known as BCP 62
|
|
|---|---|---|---|
| Authors | Gorry Fairhurst , Lloyd Wood | ||
| Last updated | 2015-10-14 | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | plain text html pdf htmlized (tools) htmlized bibtex | ||
| Stream | WG state | (None) | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 3366 (Best Current Practice) | |
| Action Holders |
(None)
|
||
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Allison Mankin | ||
| IESG note |
Published - BCP 62, RFC 3366 [note from Allison]. Responsible: Finished |
||
| Send notices to | <falk@isi.edu> | ||
Network Working Group G. Fairhurst
Request for Comments: 3366 University of Aberdeen
BCP: 62 L. Wood
Category: Best Current Practice Cisco Systems Ltd
August 2002
Advice to link designers on link Automatic Repeat reQuest (ARQ)
Status of this Memo
This document specifies an Internet Best Current Practices for the
Internet Community, and requests discussion and suggestions for
improvements. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2002). All Rights Reserved.
Abstract
This document provides advice to the designers of digital
communication equipment and link-layer protocols employing link-layer
Automatic Repeat reQuest (ARQ) techniques. This document presumes
that the designers wish to support Internet protocols, but may be
unfamiliar with the architecture of the Internet and with the
implications of their design choices for the performance and
efficiency of Internet traffic carried over their links.
ARQ is described in a general way that includes its use over a wide
range of underlying physical media, including cellular wireless,
wireless LANs, RF links, and other types of channel. This document
also describes issues relevant to supporting IP traffic over
physical-layer channels where performance varies, and where link ARQ
is likely to be used.
Fairhurst & Wood Best Current Practice [Page 1]
RFC 3366 Advice to Link Designers on Link ARQ August 2002
Table of Contents
1. Introduction. . . . . . . . . . . . . . . . . . . . . . . . .2
1.1 Link ARQ. . . . . . . . . . . . . . . . . . . . . . . . . . .4
1.2 Causes of Packet Loss on a Link . . . . . . . . . . . . . . .5
1.3 Why Use ARQ?. . . . . . . . . . . . . . . . . . . . . . . . .6
1.4 Commonly-used ARQ Techniques. . . . . . . . . . . . . . . . .7
1.4.1 Stop-and-wait ARQ . . . . . . . . . . . . . . . . . . . . . .7
1.4.2 Sliding-Window ARQ. . . . . . . . . . . . . . . . . . . . . .7
1.5 Causes of Delay Across a Link . . . . . . . . . . . . . . . .8
2. ARQ Persistence . . . . . . . . . . . . . . . . . . . . . . 10
2.1 Perfectly-Persistent (Reliable) ARQ Protocols . . . . . . . 10
2.2 High-Persistence (Highly-Reliable) ARQ Protocols. . . . . . 12
2.3 Low-Persistence (Partially-Reliable) ARQ Protocols. . . . . 13
2.4 Choosing Your Persistency . . . . . . . . . . . . . . . . . 13
2.5 Impact of Link Outages. . . . . . . . . . . . . . . . . . . 14
3. Treatment of Packets and Flows. . . . . . . . . . . . . . . 15
3.1 Packet Ordering . . . . . . . . . . . . . . . . . . . . . . 15
3.2 Using Link ARQ to Support Multiple Flows. . . . . . . . . . 16
3.3 Differentiation of Link Service Classes . . . . . . . . . . 17
4. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . 19
5. Security Considerations . . . . . . . . . . . . . . . . . . 21
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . 21
7. Acknowledgements. . . . . . . . . . . . . . . . . . . . . . 22
8. References. . . . . . . . . . . . . . . . . . . . . . . . . 22
8.1 Normative References. . . . . . . . . . . . . . . . . . . . 22
8.2 Informative References. . . . . . . . . . . . . . . . . . . 23
9. Authors' Addresses. . . . . . . . . . . . . . . . . . . . . 26
10. Full Copyright Statement. . . . . . . . . . . . . . . . . . 27
1. Introduction
IP, the Internet Protocol [RFC791], forms the core protocol of the
global Internet and defines a simple "connectionless" packet-switched
network. Over the years, Internet traffic using IP has been carried
over a wide variety of links, of vastly different capacities, delays
and loss characteristics. In the future, IP traffic can be expected
to continue to be carried over a very wide variety of new and
existing link designs, again of varied characteristics.
A companion document [DRAFTKARN02] describes the general issues
associated with link design. This document should be read in
conjunction with that and with other documents produced by the
Performance Implications of Link Characteristics (PILC) IETF
workgroup [RFC3135, RFC3155].
Fairhurst & Wood Best Current Practice [Page 2]
RFC 3366 Advice to Link Designers on Link ARQ August 2002
This document is intended for three distinct groups of readers:
a. Link designers wishing to configure (or tune) a link for the IP
traffic that it will carry, using standard link-layer mechanisms
such as the ISO High-level Data Link Control (HDLC) [ISO4335a] or
its derivatives.
b. Link implementers who may wish to design new link mechanisms that
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