End-to-end Performance Implications of Slow Links
RFC 3150
Document | Type |
RFC - Best Current Practice
(July 2001; No errata)
Also known as BCP 48
Was draft-ietf-pilc-slow (pilc WG)
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Authors | Gabriel Montenegro , Markku Kojo , Vincent Magret , Spencer Dawkins | ||
Last updated | 2013-03-02 | ||
Stream | Internent 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 3150 (Best Current Practice) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | (None) | ||
Send notices to | (None) |
Network Working Group S. Dawkins Request for Comments: 3150 G. Montenegro BCP: 48 M . Kojo Category: Best Current Practice V. Magret July 2001 End-to-end Performance Implications of Slow Links 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 (2001). All Rights Reserved. Abstract This document makes performance-related recommendations for users of network paths that traverse "very low bit-rate" links. "Very low bit-rate" implies "slower than we would like". This recommendation may be useful in any network where hosts can saturate available bandwidth, but the design space for this recommendation explicitly includes connections that traverse 56 Kb/second modem links or 4.8 Kb/second wireless access links - both of which are widely deployed. This document discusses general-purpose mechanisms. Where application-specific mechanisms can outperform the relevant general- purpose mechanism, we point this out and explain why. This document has some recommendations in common with RFC 2689, "Providing integrated services over low-bitrate links", especially in areas like header compression. This document focuses more on traditional data applications for which "best-effort delivery" is appropriate. Dawkins, et al. Best Current Practice [Page 1] RFC 3150 PILC - Slow Links July 2001 Table of Contents 1.0 Introduction ................................................. 2 2.0 Description of Optimizations ................................. 3 2.1 Header Compression Alternatives ...................... 3 2.2 Payload Compression Alternatives ..................... 5 2.3 Choosing MTU sizes ................................... 5 2.4 Interactions with TCP Congestion Control [RFC2581] ... 6 2.5 TCP Buffer Auto-tuning ............................... 9 2.6 Small Window Effects ................................. 10 3.0 Summary of Recommended Optimizations ......................... 10 4.0 Topics For Further Work ...................................... 12 5.0 Security Considerations ...................................... 12 6.0 IANA Considerations .......................................... 13 7.0 Acknowledgements ............................................. 13 8.0 References ................................................... 13 Authors' Addresses ............................................... 16 Full Copyright Statement ......................................... 17 1.0 Introduction The Internet protocol stack was designed to operate in a wide range of link speeds, and has met this design goal with only a limited number of enhancements (for example, the use of TCP window scaling as described in "TCP Extensions for High Performance" [RFC1323] for very-high-bandwidth connections). Pre-World Wide Web application protocols tended to be either interactive applications sending very little data (e.g., Telnet) or bulk transfer applications that did not require interactive response (e.g., File Transfer Protocol, Network News). The World Wide Web has given us traffic that is both interactive and often "bulky", including images, sound, and video. The World Wide Web has also popularized the Internet, so that there is significant interest in accessing the Internet over link speeds that are much "slower" than typical office network speeds. In fact, a significant proportion of the current Internet users is connected to the Internet over a relatively slow last-hop link. In future, the number of such users is likely to increase rapidly as various mobile devices are foreseen to to be attached to the Internet over slow wireless links. In order to provide the best interactive response for these "bulky" transfers, implementors may wish to minimize the number of bits actually transmitted over these "slow" connections. There are two Dawkins, et al. Best Current Practice [Page 2] RFC 3150 PILC - Slow Links July 2001 areas that can be considered - compressing the bits that make up the overhead associated with the connection, and compressing the bits that make up the payload being transported over the connection. In addition, implementors may wish to consider TCP receive window settings and queuing mechanisms as techniques to improve performanceShow full document text