RFC 1577 (rfc1577) - Page 2 of 17

Classical IP and ARP over ATM

RFC 1577             Classical IP and ARP over ATM          January 1993


1. Conventions

   The following language conventions are used in the items of
   specification in this document:

   o   MUST, SHALL, or MANDATORY -- the item is an absolute requirement
       of the specification.

   o   SHOULD or RECOMMEND -- this item should generally be followed for
       all but exceptional circumstances.

   o   MAY or OPTIONAL -- the item is truly optional and may be followed
       or ignored according to the needs of the implementor.

2.  Introduction

   The goal of this specification is to allow compatible and
   interoperable implementations for transmitting IP datagrams and ATM
   Address Resolution Protocol (ATMARP) requests and replies over ATM
   Adaptation Layer 5 (AAL5)[2,6].

   Note: this memo defines only the operation of IP and address
   resolution over ATM, and is not meant to describe the operation of
   ATM networks. Any reference to virtual connections, permanent virtual
   connections, or switched virtual connections applies only to virtual
   channel connections used to support IP and address resolution over
   ATM, and thus are assumed to be using AAL5.  This memo places no
   restrictions or requirements on virtual connections used for other
   purposes.

   Initial deployment of ATM provides a LAN segment replacement for:

      1)  Local area networks (e.g., Ethernets, Token Rings and FDDI).

      2)  Local-area backbones between existing (non-ATM) LANs.

      3)  Dedicated circuits or frame relay PVCs between IP routers.

   Note: In 1), local IP routers with one or more ATM interfaces will be
   able to connect islands of ATM networks.  In 3), public or private
   ATM Wide Area networks will be used to connect IP routers, which in
   turn may or may not connect to local ATM networks.  ATM WANs and LANs
   may be interconnected.

   Private ATM networks (local or wide area) will use the private ATM
   address structure specified in the ATM Forum UNI specification [9].
   This structure is modeled after the format of an OSI Network Service
   Access Point Address.  A private ATM address uniquely identifies an



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