CATNIP: Common Architecture for the Internet
RFC 1707

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Network Working Group:                                       M. McGovern
Request for Comments: 1707                              Sunspot Graphics
Category: Informational                                       R. Ullmann
                                           Lotus Development Corporation
                                                            October 1994

              CATNIP: Common Architecture for the Internet

Status of this Memo

   This memo provides information for the Internet community.  This memo
   does not specify an Internet standard of any kind.  Distribution of
   this memo is unlimited.

Abstract

   This document was submitted to the IETF IPng area in response to RFC
   1550  Publication of this document does not imply acceptance by the
   IPng area of any ideas expressed within.  Comments should be
   submitted to the big-internet@munnari.oz.au mailing list.

Executive Summary

   This paper describes a common architecture for the network layer
   protocol. The Common Architecture for Next Generation Internet
   Protocol (CATNIP) provides a compressed form of the existing network
   layer protocols. Each compression is defined so that the resulting
   network protocol data units are identical in format. The fixed part
   of the compressed format is 16 bytes in length, and may often be the
   only part transmitted on the subnetwork.

   With some attention paid to details, it is possible for a transport
   layer protocol (such as TCP) to operate properly with one end system
   using one network layer (e.g. IP version 4) and the other using some
   other network protocol, such as CLNP. Using the CATNIP definitions,
   all the existing transport layer protocols used on connectionless
   network services will operate over any existing network layer
   protocol.

   The CATNIP uses cache handles to provide both rapid identification of
   the next hop in high performance routing as well as abbreviation of
   the network header by permitting the addresses to be omitted when a
   valid cache handle is available. The fixed part of the network layer
   header carries the cache handles.

McGovern & Ullmann                                              [Page 1]
RFC 1707                         CATNIP                     October 1994

   The cache handles are either provided by feedback from the downstream
   router in response to offered traffic, or explicitly provided as part
   of the establishment of a circuit or flow through the network. When
   used for flows, the handle is the locally significant flow
   identifier.

   When used for circuits, the handle is the layer 3 peer-to-peer
   logical channel identifier, and permits a full implementation of
   network-layer connection-oriented service if the routers along the
   path provide sufficient features. At the same time, the packet format
   of the connectionless service is retained, and hop by hop fully
   addressed datagrams can be used at the same time. Any intermediate
   model between the connection oriented and the connectionless service
   can thus be provided over cooperating routers.

CATNIP Objectives

   The first objective of the CATNIP is a practical recognition of the
   existing state of internetworking, and an understanding that any
   approach must encompass the entire problem. While it is common in the
   IP Internet to dismiss the ISO with various amusing phrases, it is
   hardly realistic. As the Internet moves into the realm of providing
   real commercial infrastructure, for telephone, cable television, and
   the myriad other mundane uses, compliance with international
   standards is an imperative.

   The argument that the IETF need not (or should not) follow existing
   ISO standards will not hold. The ISO is the legal standards
   organization for the planet. Every other industry develops and
   follows ISO standards. There is (no longer) anything special about
   computer software or data networking.

   ISO convergence is both necessary and sufficient to gain
   international acceptance and deployment of IPng. Non-convergence will
   effectively preclude deployment.

   The CATNIP integrates CLNP, IP, and IPX. The CATNIP design provides
   for any of the transport layer protocols in use, for example TP4,
   CLTP, TCP, UDP, IPX and SPX to run over any of the network layer
   protocol formats: CLNP, IP (version 4), IPX, and the CATNIP.

Incremental Infrastructure Deployment

   The best use of the CATNIP is to begin to build a common Internet
   infrastructure. The routers and other components of the common system
   are able to use a single consistent addressing method, and common
   terms of reference for other aspects of the system.

McGovern & Ullmann                                              [Page 2]
RFC 1707                         CATNIP                     October 1994

   The CATNIP is designed to be incrementally deployable in the strong
   sense: you can plop a CATNIP system down in place of any existing