During the early 1990s, the explosive growth of the World Wide Web accelerated the consumption of 32-bit IPv4 addresses, raising alarms among internet engineers that the unallocated address space would be entirely exhausted within a decade. Recognizing that the original 4.3 billion address limit was insufficient for a global user base, the Internet Engineering Task Force (IETF) initiated the IP Next Generation (IPng) effort in 1992 to design a successor protocol.
In December 1995, the IETF published RFC 1883, formalizing the specification for Internet Protocol, Version 6 (IPv6). Authored by Steve Deering of Xerox PARC and Bob Hinden of Ipsilon Networks, the specification expanded IP address sizes from 32 bits to 128 bits. This change drastically expanded the total address space to approximately 3.4 x 10^38 unique addresses—enough to assign trillions of addresses to every person on Earth.
Beyond solving address exhaustion, RFC 1883 streamlined header structures to accelerate router processing, integrated stateless address autoconfiguration (SLAAC), and built in native support for network-level encryption (IPsec). While adoption moved slowly due to the widespread deployment of temporary fixes like Network Address Translation (NAT), RFC 1883 established the architectural bedrock that guarantees the unlimited future growth of the global Internet.
Why it matters
RFC 1883 provided the definitive long-term solution to IPv4 address exhaustion, securing the Internet's ability to expand indefinitely. By extending addresses to 128 bits, IPv6 eliminated the threat of running out of unique IP addresses for modern mobile phones, IoT devices, and cloud computing infrastructure. Additionally, its simplified header layout and built-in security mechanisms modernized fundamental networking protocols for the 21st century.
Interesting fact
IPv5 was skipped as the successor to IPv4 because protocol version number 5 had already been assigned to the Internet Stream Protocol Version 2 (ST2), an experimental voice streaming protocol tested in the 1980s.
People
- Steve DeeringCo-author of RFC 1883 and inventor of IP multicast
- Robert HindenCo-author of RFC 1883 and Co-chair of IETF IPng Working Group
- Scott BradnerCo-chair of the IETF IPng Area Directorate
Quotes
"This document specifies version 6 of the Internet Protocol (IPv6), also referred to as IP Next Generation (IPng)."
Location
IETF Secretariat · San Jose · United States
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