Network Working Group                                          B. Leiner
Request for Comments: 1560                                          USRA
Category: Informational                                       Y. Rekhter
                                                           December 1993

                       The MultiProtocol 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.


   This document was prepared by the authors on behalf of the Internet
   Architecture Board (IAB).  It is offered by the IAB to stimulate

   There has recently been considerable discussion on two topics:
   MultiProtocol approaches in the Internet and the selection of a next
   generation Internet Protocol. This document suggests a strawman
   position for goals and approaches for the IETF/IESG/IAB in these
   areas. It takes the view that these two topics are related, and
   proposes directions for the IETF/IESG/IAB to pursue.

   In particular, it recommends that the IETF/IESG/IAB should continue
   to be a force for consensus on a single protocol suite and internet
   layer protocol. The IETF/IESG/IAB should:

      - maintain its focus on the TCP/IP protocol suite,

      - work to select a single next-generation internet protocol and
        develop mechanisms to aid in transition from the current IPv4,

      - continue to explore mechanisms to interoperate and share
        resources with other protocol suites within the Internet.

1.  Introduction

   The major purpose of the Internet is to enable ubiquitous
   communication services between endpoints. In a very real way, the
   Internet IS inter-enterprise networking. Therefore, the issue of
   multiprotocol Internet is not just the issue of multiple network
   layers, but the issue of multiple comparable services implemented

Internet Architecture Board                                     [Page 1]
RFC 1560               The MultiProtocol Internet          December 1993

   over different protocols.

   The issue of multiprotocol Internet is multidimensional and should be
   analyzed with respect to two simultaneous principles:

      - It is desirable to have a single protocol stack. The community
        should try to avoid unconstrained proliferation of various
        protocol stacks.

      - In reality there will always be more than one protocol stack.
        Presence of multiple network layers is just one of the
        corollaries of this observation, as even within a single
        protocol stack, forces of evolution of that stack will lead
        to periods of multiple protocols.  We need to develop
        mechanisms that maximize the services that can be provided
        across all the protocol stacks (multiprotocol Internet).

2.  Background and Context

2.1.  The MultiProtocol Evolutionary Process

   In an IAB architectural retreat held in 1991 [Cla91], a dynamic view
   of the process of multiprotocol integration and accommodation was
   described, based on the figure below.

            ---------------             --------------
            !             !             !            !
            !             !             ! Interop-   !
            ! Primary     ! >>>>>>>>>>> ! erability  !>>>>>
            ! Protocol    !             !            !    v
            ! Suite       !             --------------    v
            !             !                               v
            !             !                               v
            !             !             --------------    v
            !             !             !            !    v
            !             ! >>>>>>>>>>> !  Resource  !    v
            !             !             !  Sharing   !>>>>v
            !             !             !            !    v
            ---------------             --------------    v
                  ^                                       v
                  ^      --------------                   v
                  ^      !            !                   v