# Synchronous PPP and Cisco HDLC Programming Guide

Alan
Cox

          alan@lxorguk.ukuu.org.uk

2000
Alan Cox

This documentation is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

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For more details see the file COPYING in the source distribution of Linux.

## Introduction

The syncppp drivers in Linux provide a fairly complete implementation of Cisco HDLC and a minimal implementation of PPP. The longer term goal is to switch the PPP layer to the generic PPP interface that is new in Linux 2.3.x. The API should remain unchanged when this is done, but support will then be available for IPX, compression and other PPP features

## Known Bugs And Assumptions

PPP is minimal

  The current PPP implementation is very basic, although sufficient for most wan usages.

Cisco HDLC Quirks

  Currently we do not end all packets with the correct Cisco multicast or unicast flags. Nothing appears to mind too much but this should be corrected.

## Public Functions Provided

!Edrivers/net/wan/syncppp.c