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
|
|
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Authors | Gorry Fairhurst , Lloyd Wood | ||
Last updated | 2015-10-14 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 3366 (Best Current Practice) | |
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 thatShow full document text