The PPP SNA Control Protocol (SNACP)
RFC 2043

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Network Working Group                                           A. Fuqua
Request for Comments: 2043                                           IBM
Category: Standards Track                                   October 1996

                  The PPP SNA Control Protocol (SNACP)

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) 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 for
   transporting multi-protocol datagrams over point-to-point links.  PPP
   defines an extensible Link Control Protocol, and proposes a family of
   Network Control Protocols for establishing and configuring different
   network-layer protocols.

   This document defines the Network Control Protocols for establishing
   and configuring Systems Network Architecture (SNA) over PPP and SNA
   over LLC 802.2 over PPP.

Table of Contents

   1.     Introduction ..........................................    2
      1.1       Specification of Requirements ...................    2
      1.2       Terminology .....................................    3
   2.     A PPP Network Control Protocol for SNA ................    4
   3.     Sending SNA PIUs and NLPs. ............................    5
      3.1       Sending SNA XID or FID2 PIUs over LLC ...........    5
      3.2       Sending HPR Network Layer Packets (NLPs) ........    5
      3.3       Other Considerations ............................    6
   SECURITY CONSIDERATIONS ......................................    6
   REFERENCES ...................................................    6
   ACKNOWLEDGEMENTS... ..........................................    7
   CHAIR'S ADDRESS ..............................................    7
   AUTHOR'S ADDRESS .............................................    7

Fuqua                       Standards Track                     [Page 1]
RFC 2043                       PPP SNACP                    October 1996

1.  Introduction

   PPP has three main components:

   1. A method for encapsulating multi-protocol datagrams.

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

   3. A family of Network Control Protocols 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
   SNACP packets to choose and configure the SNA network-layer protocol.
   Once SNACP has reached the Opened state, SNA datagrams can be sent
   over the link.

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

1.1.  Specification of Requirements

   In this document, several words are used to signify the requirements
   of the specification.  These words are often capitalized.

   MUST      This word, or the adjective "required", means that the
             definition is an absolute requirement of the specification.

   MUST NOT  This phrase means that the definition is an absolute
             prohibition of the specification.

   SHOULD    This word, or the adjective "recommended", means that there
             may exist valid reasons in particular circumstances to
             ignore this item, but the full implications must be
             understood and carefully weighed before choosing a
             different course.

   MAY       This word, or the adjective "optional", means that this
             item is one of an allowed set of alternatives.  An
             implementation which does not include this option MUST be
             prepared to interoperate with another implementation which
             does include the option.

Fuqua                       Standards Track                     [Page 2]
RFC 2043                       PPP SNACP                    October 1996

1.2.  Terminology

   This document frequently uses the following terms:

   datagram  The unit of transmission in the network layer (such as IP).
             A datagram may be encapsulated in one or more packets
             passed to the data link layer.

   frame     The unit of transmission at the data link layer.  A frame
             may include a header and/or a trailer, along with some
             number of units of data.

   packet    The basic unit of encapsulation, which is passed across the
             interface between the network layer and the data link