RFC 1705 (rfc1705) - Page 3 of 27

Six Virtual Inches to the Left: The Problem with IPng

RFC 1705     Six Virtual Inches to the Left: IPng Problems  October 1994


   IP.

   The motivation for writing this paper resulted from research into the
   various Internet Protocol Next Generation (IPng) proposals put forth
   by various IETF working groups. Each of the IPng proposals strives to
   solve the impending IP address exhaustion problem by increasing the
   size of the address field. They all allude to modifications to TCP
   and User Datagram Protocol (UDP) to make them capable of supporting a
   new network layer IPng protocol. The authors of this paper feel that
   this points to an inherent TCP/IP design flaw. The flaw is namely
   that the transport (TCP) and network (IP) layers are not protocol
   independent. In this paper, we will propose a new TCP and UDP
   implementation that will make the transport and protocol layers
   independent and thus allow for any of the IPng protocols to operate
   on the same internet without any further modification to the higher
   layer protocols.  TCP, and UDP would become extremely powerful
   Application Programming Interfaces (APIs) that operate effectively
   over multiple network layer technologies.

2.  Historical perspective

2.1  OSI and the 7 layer model

   Present day computer and communication systems have become
   increasingly heterogeneous in both their software and hardware
   complexity, as well as their intended functionality. Prior to the
   establishment of computer communications industry standards,
   proprietary standards followed by particular software and hardware
   manufacturers prevented communication and information exchange
   between different manufacturers  products and therefore lead to many
   "closed systems" [Halsal, 1992] incapable of readily sharing
   information. With the proliferation of these types of systems in the
   mid 1970s, the potential advantages of "open systems" where
   recognized by the computer industry and a range of standards started
   to be introduced [Halsal, 1992].

   The first and perhaps most important of these standards was the
   International Standards Organization (ISO) reference model for Open
   Systems Interconnection standard (OSI), describing the complete
   communication subsystem within each computer. The goal of this
   standard model was to "allow an application process in any computer
   that supports a particular set of standards to communicate freely
   with an application process in any other computer that supports the
   same standards, irrespective of its origin of manufacture" [Halsal,
   1992].  The last statement above describes the OSI 7-layer model
   which has now, in concept, become the fundamental building block of
   computer networks.  Though there are arguably no present day
   computers and networks completely compliant to all 7 layers of the



Carlson & Ficarella