RFC 1385 (rfc1385) - Page 2 of 17

EIP: The Extended Internet Protocol

RFC 1385                          EIP                      November 1992


   development and deployment of such a new "Internet" would take a very
   large amount of time and effort. In particular, in order to maintain
   interoperability between the old and new systems during the
   transition period, almost all upgraded systems have to run both the
   new and old versions in parallel and also have to determine which
   version to use depending on whether the other side is upgraded or
   not.

   Let us now have a look at the detailed changes that will be required
   to replace the current IP with a completely new "IP" and to maintain
   the interoperability between the new and the old systems.

   1) Border Routers: Border routers have to be upgraded and to provide
      address translation service for IP packets across the boundaries.
      Note that the translation has to be done on the outgoing IP
      packets as well as the in-coming packets to IP hosts.

   2) Subnet Routers: Subnet Routers have to be upgraded and have to
      deal with both the new and the old packet formats.

   3) Hosts: Hosts have to be upgraded and run both the new and the
      old protocols in parallel. Upgraded hosts also have to determine
      whether the other side is upgraded or not in order to choose the
      correct protocol to use.

   4) DNS: The DNS has to be modified to provide mapping for domain
      names and new addresses.

   5) ARP/RARP: ARP/RARP have to be modified, and upgraded hosts and
      routers have to deal with both the old and new ARP/RARP packets.

   6) ICMP: ICMP has to be modified, and the upgraded routers have to
      be able to generate both both old and new ICMP packets.  However,
      it may be impossible for a backbone router to determine
      whether the packet comes from an upgraded host or an IP host but
      translated by the border router.

   7) TCP/UDP Checksum: The pseudo headers may have to be modified to
      use the new addresses.

   8) FTP: The DATA PORT (PORT) command has to be changed to pass new
      addresses.

   In this paper, we argue that an evolutionary approach can extend the
   addressing space yet maintain backward compatibility.  The Extended
   Internet Protocol (EIP) we present here can be used as a framework by
   which a new routing and addressing scheme may solve the problem of
   address exhaustion yet maintain maximum backward compatibility to



Wang