Use of the Internet as a subnetwork for experimentation with the OSI network layer
Network Working Group R. Hagens
Request for Comments: 1070 U of Wiscsonsin - Madison
U of Wiscsonsin - Madison
The Wollongong Group
Use of the Internet as a Subnetwork for
Experimentation with the OSI Network Layer
Status of this Memo
This RFC proposes a scenario for experimentation with the
International Organization for Standardization (ISO) Open Systems
Interconnection (OSI) network layer protocols over the Internet and
requests discussion and suggestions for improvements to this
scenario. This RFC also proposes the creation of an experimental OSI
internet. To participate in the experimental OSI internet, a system
must abide by the agreements set forth in this RFC. Distribution of
this memo is unlimited.
The methods proposed in this RFC are suitable ONLY for experimental
use on a limited scale. These methods are not suitable for use in an
Since the International Organization for Standardization (ISO) Open
Systems Interconnection (OSI) network layer protocols are in their
infancy, both interest in their development and concern for their
potential impact on internetworking are widespread. This interest
has grown substantially with the introduction of the US Government
OSI Profile (GOSIP), which mandates, for the US Government, the use
of OSI products in the near future. The OSI network layer protocols
have not yet received significant experimentation and testing. The
status of the protocols in the OSI network layer varies from ISO
International Standard to "contribution" (not yet a Draft Proposal).
We believe that thorough testing of the protocols and implementations
of the protocols should take place concurrently with the progression
of the protocols to ISO standards. For this reason, the creation of
an environment for experimentation with these protocols is timely.
Thorough testing of network and transport layer protocols for
Hagens, Hall, & Rose [Page 1]
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.
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