Illustrated TCP/IP by Matthew G. Naugle Wiley Computer Publishing, John Wiley & Sons, Inc. ISBN: 0471196568   Pub Date: 11/01/98

Chapter 141
From IPv4 to IPv6

IPv6 was not the result of one meeting. Many proposals were developed and algorithms were experimented with before being presented.

One proposal that had a lot of support wanted to replace IP with the ISO (Inter-national Organization for Standardization) OSI CLNP Protocol. ISO CLNP (Connectionless Protocol), which was demonstrated as TUBA (TCP and UDP over Bigger Addresses. RFCs 1247, 1526, and 1561).

With many changes to the TCP and IP layers, IP version 7 (also known as TP/IX. RFC 1475) eventually evolved into the CATNIP (RFC 1707).

IP in IP evolved into IPAE (IP Address Encapsulation). It proposed running two layers of the IP protocol, one for the worldwide backbone and one for the regional IP networks. This eventually evolved into Simple IP, or SIP. This moved the address to 64 bits and did away with some of the unused features of ICMP.

During 1992 and 1993, the Pip internet protocol, developed at Bleacher, was one of the candidate replacements for IP. It had many improvements in routing strategies and in mid-1993, Pip was merged with the Simple Internet Protocol (SIP), creating SIPP (SIP Plus).

SIPP (RFC 1710) is a new version of IP designed to be an evolutionary step from IPv4. It can be installed as a normal software upgrade in internet devices and is interoperable with the current IPv4.

While it is true that IPv6 solves the addressing problem, as you can see from the preceding list, it has a few other properties that improved upon the IPv4 protocol.