The PPP AppleTalk Control Protocol (ATCP)
RFC 1378

Network Working Group                                          B. Parker
Request for Comments: 1378                                Cayman Systems
                                                           November 1992

               The PPP AppleTalk Control Protocol (ATCP)

Status of this Memo

   This RFC specifies an IAB standards track protocol for the Internet
   community, and requests discussion and suggestions for improvements.
   Please refer to the current edition of the "IAB Official Protocol
   Standards" for the standardization state and status of this protocol.
   Distribution of this memo is unlimited.

Abstract

   The Point-to-Point Protocol (PPP) [1] provides a standard method of
   encapsulating Network Layer protocol information over point-to-point
   links.  PPP also defines an extensible Link Control Protocol, and
   proposes a family of Network Control Protocols (NCPs) for
   establishing and configuring different network-layer protocols.

   This document defines the NCP for establishing and configuring the
   AppleTalk Protocol [3] over PPP.

   This memo is a joint effort of the AppleTalk-IP Working Group and the
   Point-to-Point Protocol Working Group of the Internet Engineering
   Task Force (IETF).  Comments on this memo should be submitted to the
   ietf-ppp@ucdavis.edu mailing list.

Table of Contents

   1.     Introduction ..........................................    2
   2.     A PPP Network Control Protocol (NCP) for AppleTalk ....    2
   2.1    Sending AppleTalk Datagrams ...........................    3
   2.2    Half-Routers ..........................................    4
   3.     ATCP Configuration Options ............................    4
   3.1    AppleTalk-Address .....................................    5
   3.2    Routing-Protocol ......................................    7
   3.3    Suppress-Broadcasts ...................................    8
   3.4    AT-Compression-Protocol ...............................    9
   3.5    Server-information ....................................   10
   3.6    Zone-Information ......................................   12
   3.7    Default-Router-Address ................................   13
   APPENDICES ...................................................   14
   A.     ATCP Recommended Options ..............................   14
   REFERENCES ...................................................   15

Parker                                                          [Page 1]
RFC 1378                        PPP ATCP                   November 1992

   ACKNOWLEDGEMENTS .............................................   15
   SECURITY CONSIDERATIONS ......................................   16
   CHAIR'S ADDRESS ..............................................   16
   AUTHOR'S ADDRESS .............................................   16

1.  Introduction

   PPP has three main components:

      1. A method for encapsulating datagrams over serial links.

      2. A Link Control Protocol (LCP) for establishing, configuring,
         and testing the data-link connection.

      3. A family of Network Control Protocols (NCPs) for establishing
         and configuring different network-layer protocols.

   In order to establish communications over a point-to-point link, each
   end of the PPP link must first send LCP packets to configure and test
   the data link.  After the link has been established and optional
   facilities have been negotiated as needed by the LCP, PPP must send
   NCP packets to choose and configure one or more network-layer
   protocols.  Once each of the chosen network-layer protocols has been
   configured, datagrams from each network-layer protocol can be sent
   over the link.

   The link will remain configured for communications until explicit LCP
   or NCP packets close the link down, or until some external event
   occurs (an inactivity timer expires or network administrator
   intervention).

2.  A PPP Network Control Protocol (NCP) for AppleTalk

   The AppleTalk Control Protocol (ATCP) is responsible for configuring,
   enabling, and disabling the AppleTalk protocol modules on both ends
   of the point-to-point link.  ATCP uses the same packet exchange
   machanism as the Link Control Protocol (LCP).  ATCP packets may not
   be exchanged until PPP has reached the Network-Layer Protocol phase.
   ATCP packets received before this phase is reached should be silently
   discarded.

   The AppleTalk Control Protocol is exactly the same as the Link
   Control Protocol [1] with the following exceptions:

   Frame Modifications

      The packet may utilize any modifications to the basic frame format
      which have been negotiated during the Link Establishment phase.

Parker                                                          [Page 2]