RFC 1974 (rfc1974) - Page 1 of 20


PPP Stac LZS Compression Protocol



Alternative Format: Original Text Document



Network Working Group                                          R. Friend
Request for Comments: 1974                              Stac Electronics
Category: Informational                                       W. Simpson
                                                              DayDreamer
                                                             August 1996


                   PPP Stac LZS Compression Protocol

Status of this Memo

   This memo provides information for the Internet community.  This memo
   does not specify an Internet standard of any kind.  Distribution of
   this memo is unlimited.

Abstract

   The Point-to-Point Protocol (PPP) [1] provides a standard method for
   transporting multi-protocol datagrams over point-to-point links.

   The PPP Compression Control Protocol [2] provides a method to
   negotiate and utilize compression protocols over PPP encapsulated
   links.

   This document describes the use of the Stac LZS data compression
   algorithm, with single or multiple compression histories, for
   compressing PPP encapsulated packets.

Table of Contents

     1.     Introduction ..........................................    2
        1.1       Licensing .......................................    2
        1.2       Specification of Requirements ...................    3
     2.     LZS Packets ...........................................    3
        2.1       Padding .........................................    4
        2.2       Zero Deletion/Insertion .........................    4
        2.3       Reliability and Sequencing ......................    4
           2.3.1  Reset-Request and Reset-Ack Packet Formats.......    5
        2.4       Data Expansion ..................................    6
        2.5       Packet Format ...................................    6
           2.5.1  PPP Protocol ....................................    7
           2.5.2  History Number ..................................    7
           2.5.3  Check Value .....................................    7
              2.5.3.1  LCB ........................................    7
              2.5.3.2  CRC ........................................    7
              2.5.3.3  Sequence Number ............................    8
                 2.5.3.3.1  History Synchronization with Sequence
                             Numbers Example ......................    9



Friend & Simpson             Informational