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PPP Gandalf FZA Compression Protocol (RFC1993)

IP.com Disclosure Number: IPCOM000004269D
Original Publication Date: 1996-Aug-01
Included in the Prior Art Database: 2019-Feb-14
Document File: 7 page(s) / 7K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

A. Barbir: AUTHOR [+2]

Related Documents

10.17487/RFC1993: DOI

Abstract

This document describes the use of the Gandalf FZA data compression algorithm [3] for compressing PPP encapsulated packets. This memo provides information for the Internet community. It does not specify an Internet standard.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 39% of the total text.

Network Working Group A. Barbir Request for Comments: 1993 Gandalf Category: Informational D. Carr Newbridge W. Simpson DayDreamer August 1996

PPP Gandalf FZA Compression Protocol

Status of this Memo

This memo provides information for the Internet community. It does not specify an Internet standard. 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 Gandalf FZA data compression algorithm [3] for compressing PPP encapsulated packets.

Table of Contents

1. Introduction .......................................... 1 1.1 Licensing ....................................... 1 2. FZA Packets ........................................... 2 2.1 Packet Format ................................... 3 3. Configuration Option Format ........................... 4 SECURITY CONSIDERATIONS ...................................... 4 ACKNOWLEDGEMENTS ............................................. 5 REFERENCES ................................................... 5 CONTACTS ..................................................... 5

Barbir, Carr & Simpson [Page i]

RFC 1993 Gandalf FZA August 1996

1. Introduction

FZA is a high performance LZ [4] derivative that maximizes compression at the expense of memory and CPU. Compression performance can be adjusted based on CPU and memory available.

Multiple PPP packets can be combined in a single compressed frame, or a single PPP packet can be spread across multiple frames.

1.1. Licensing

Source and object licenses are available on a non-discriminatory basis for either a royalty or fixed price arrangement. Patent indemnity is included with the license.

Barbir, Carr & Simpson [Page 1]

RFC 1993 Gandalf FZA August 1996

2. FZA Packets

Before any FZA packets may be communicated, PPP must reach the Network-Layer Protocol phase.

When the Compression Control Protocol (CCP) has reached the Opened state, and FZA is negotiated as the primary compression algorithm, the PPP Protocol field indicates type hex 00FB (link compressed datagram), or type hex 00FD (compressed datagram).

The maximum length of the FZA datagram transmitted over a PPP link is the same as the maximum length of the Information field of a PPP encapsulated packet.

Padding

The FZA packets require the negotiation of the Self-Describing- Padding Configuration Option [5] at LCP Link Establishment.

Reliability and Sequencing

The FZA algorithm expects a reliable link, as described in "PPP Reliable Transmission" [6].

FZA expects the packets to be delivered in sequence.

Data Expansion

The maximum expansion of Gandalf FZA is 2:1. However, typical expansion on pre-compressed data is 1.01:1. Expanded data is sent to maintain the integrity of the compression history.

When the expansion exceeds the...

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