IP Payload Compression Using LZS
RFC 2395
Document | Type |
RFC - Informational
(December 1998; Errata)
Was draft-ietf-ippcp-lzs (ippcp WG)
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Authors | Robert Friend , Robert Monsour | ||
Last updated | 2020-01-21 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized with errata bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 2395 (Informational) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | (None) | ||
Send notices to | (None) |
Network Working Group R. Friend Request for Comments: 2395 R. Monsour Category: Informational Hi/fn, Inc. December 1998 IP Payload Compression Using LZS Status of this Memo This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (1998). All Rights Reserved. Abstract This document describes a compression method based on the LZS compression algorithm. This document defines the application of the LZS algorithm to the IP Payload Compression Protocol [IPCOMP]. [IPCOMP] defines a method for applying lossless compression to the payloads of Internet Protocol datagrams. Table of Contents 1. Introduction...................................................2 1.1 General....................................................2 1.2 Background of LZS Compression..............................2 1.3 Licensing..................................................3 1.4 Specification of Requirements..............................3 2. Compression Process............................................3 2.1 Compression History........................................3 2.2 Compression Encoding Format................................3 2.3 Padding....................................................4 3. Decompression Process..........................................4 4. IPComp Association (IPCA) Parameters...........................4 4.1 ISAKMP Transform ID........................................5 4.2 ISAKMP Security Association Attributes.....................5 4.3 Manual configuration.......................................5 4.4 Minimum packet size threshold..............................5 4.5 Compressibility test.......................................5 5. Security Considerations........................................5 6. Acknowledgements...............................................5 7. References.....................................................6 8. Authors' Addresses.............................................7 Friend & Monsour Informational [Page 1] RFC 2395 IP Payload Compression Using LZS December 1998 9. Appendix: Compression Efficiency versus Datagram Size..........8 10. Full Copyright Statement......................................9 1. Introduction 1.1 General This document specifies the application of LZS compression, a lossless compression algorithm, to IP datagram payloads. This document is to be used in conjunction with the IP Payload Compression Protocol [IPCOMP]. This specification assumes a thorough understanding of the IPComp protocol. 1.2 Background of LZS Compression Starting with a sliding window compression history, similar to [LZ1], Hi/fn developed a new, enhanced compression algorithm identified as LZS. The LZS algorithm is a general purpose lossless compression algorithm for use with a wide variety of data types. Its encoding method is very efficient, providing compression for strings as short as two octets in length. The LZS algorithm uses a sliding window of 2,048 bytes. During compression, redundant sequences of data are replaced with tokens that represent those sequences. During decompression, the original sequences are substituted for the tokens in such a way that the original data is exactly recovered. LZS differs from lossy compression algorithms, such as those often used for video compression, that do not exactly reproduce the original data. The details of LZS compression can be found in [ANSI94]. The efficiency of the LZS algorithm depends on the degree of redundancy in the original data. A table of compression ratios for the [Calgary] Corpus file set is provided in the appendix in Section 7. Friend & Monsour Informational [Page 2] RFC 2395 IP Payload Compression Using LZS December 1998 1.3 Licensing Hi/fn, Inc. holds patents on the LZS algorithm. Licenses for a reference implementation are available for use in IPPCP, IPSec, TLS and PPP applications at no cost. Source and object licenses are available on a non-discriminatory basis. Hardware implementations are also available. For more information, contact Hi/fn at the address listed with the authors' addresses. 1.4 Specification of Requirements The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC-2119]. 2. Compression ProcessShow full document text