RFC 1475 (rfc1475) - Page 3 of 35

TP/IX: The Next Internet

RFC 1475                         TP/IX                         June 1993


   7.2       PTR zone  . . . . . . . . . . . . . . . . . . . .  25
   8.       Conversion between version 4 and version 7 . . . .  25
   8.1       Version 4 IP address extension option . . . . . .  26
   8.1.1     Option format . . . . . . . . . . . . . . . . . .  26
   8.2      Fragmented datagrams . . . . . . . . . . . . . . .  26
   8.3      Where does the conversion happen?  . . . . . . . .  27
   8.4      Hybrid IPv4 systems  . . . . . . . . . . . . . . .  28
   8.5      Maximum segment size in TCP  . . . . . . . . . . .  28
   8.6      Forwarding and redirects . . . . . . . . . . . . .  28
   8.7      Design considerations  . . . . . . . . . . . . . .  28
   8.8      Conversion from IPv4 to IPv7 . . . . . . . . . . .  29
   8.9      Conversion from IPv7 to IPv4 . . . . . . . . . . .  30
   8.10     Conversion from TCPv4 to TCPv7 . . . . . . . . . .  31
   8.11     Conversion from TCPv7 to TCPv4 . . . . . . . . . .  32
   8.12     ICMP conversion  . . . . . . . . . . . . . . . . .  33
   9.       Postscript . . . . . . . . . . . . . . . . . . . .  33
   10.      References . . . . . . . . . . . . . . . . . . . .  34
   11.      Security Considerations  . . . . . . . . . . . . .  35
   12.      Author's Address . . . . . . . . . . . . . . . . .  35

1.  Introduction

   This memo presents the specification for version 7 of the Internet
   Protocol, as well as version 7 of the TCP and the user datagram
   protocol.  Version 7 has been designed to address several major
   problems that have arisen as version 4 has evolved and been deployed,
   and to make a major step forward in the datagram switching and
   forwarding architecture of the Internet.

   The major problems are threefold.  First, the address space of
   version 4 is now seen to be too small.  While it was viewed as being
   almost impossibly large when version 4 was designed, two things have
   occurred to create a problem.  The first is a success crisis:  the
   internet protocols have been more widely used and accepted than their
   designers anticipated.  Also, technology has moved forward, putting
   microprocessors into devices not anticipated except as future dreams
   a decade ago.

   The second major problem is a perceived routing explosion.  The
   present routing architecture of the internet calls for routing each
   organization's network independently.  It is becoming increasingly
   clear that this does not scale to a universal internet.  While it is
   possible to route several billion networks in a flat, structureless
   domain, it is not desireable.

   There is also the political administrative issue of assigning network
   numbers to organizations.  The version 4 administrative system calls
   for organizations to request network assignments from a single



Ullmann