RFC 1070 (rfc1070) - Page 2 of 17

Use of the Internet as a subnetwork for experimentation with the OSI network layer

RFC 1070                  Experimental OSI Net             February 1989


   internetworking requires a large, varied, and complex environment.
   While an implementor of the OSI protocols may of course test an
   implementation locally, few implementors have the resources to create
   a sufficiently large dynamic topology in which to test the protocols
   and implementations well.

   One way to create such an environment is to implement the OSI network
   layer protocols in the existing routers in an existing internetwork.
   This solution is likely to be disruptive due to the immature state of
   the OSI network layer protocols and implementations, coupled with the
   fact that a large set of routers would have to implement the OSI
   network layer in order to do realistic testing.

   This memo suggests a scenario that will make it easy for implementors
   to test with other implementors, exploiting the existing connectivity
   of the Internet without disturbing existing gateways.

   The method suggested is to treat the Internet as a subnetwork,
   hereinafter called the "IP subnet."  We do this by encapsulating OSI
   connectionless network layer protocol (ISO 8473) packets in IP
   datagrams, where IP refers to the Internet network layer protocol,
   RFC 791.  This encapsulation occurs only with packets travelling over
   the IP subnet to sites not reachable over a local area network.  The
   intent is for implementations to use OSI network layer protocols
   directly over links locally, and to use the IP subnet as a link only
   when necessary to reach a site that is separated from the source by
   an IP gateway.  While it is true that almost any system at a
   participating site may be reachable with IP, it is expected that
   experimenters will configure their systems so that a subset of their
   systems will consider themselves to be directly connected to the IP
   subnet for the purpose of testing the OSI network layer protocols or
   their implementations.  The proposed scheme permits systems to change
   their topological relationship to the IP subnet at any time, also to
   change their behavior as an end system (ES), intermediate system
   (IS), or both at any time.  This flexibility is necessary to test the
   dynamic adaptive properties of the routing exchange protocols.

   A variant of this scheme is proposed for implementors who do not have
   direct access to the IP layer in their systems.  This variation uses
   the User Datagram Protocol over IP (UDP/IP) as the subnetwork.

   In this memo we will call the experiment based on the IP subnet EON,
   an acronym for "Experimental OSI-based Network".  We will call the
   experiment based on the UDP/IP subnet EON-UDP.

   It is assumed that the reader is familiar with the OSI connectionless
   network layer and, in particular, with the following documents:




Hagens, Hall, & Rose