List of IP version numbers
Packets that hold Internet Protocol data carry a 4-bit IP version number as the first field of its header.[1][2] Currently, only IPv4 and IPv6 packets are seen on the Internet, having IP version numbers 4 and 6, respectively.
IP version numbers
As the version number is carried in a 4-bit field, only numbers 0-15 can be assigned.
IP version | Description | Status |
---|---|---|
0 | Reserved.[3] | |
1-3 | Unassigned. | |
4 | Internet Protocol version 4 (IPv4)[1] | Active. |
5 | Internet Stream Protocol or ST | Obsolete; superseded by ST-II. |
5 | Internet Stream Protocol or ST-II[4] | Obsolete. |
6 | Simple Internet Protocol (SIP) | Obsolete; merged into IPv6.[3] |
6 | Internet Protocol version 6 (IPv6)[2] | Active. |
7 | TP/IX The Next Internet (IPv7)[5] | Obsolete.[6] |
8 | P Internet Protocol (PIP)[7] | Obsolete; merged into SIP in 1993. |
9 | TCP and UDP over Bigger Addresses (TUBA) | Obsolete.[8] |
9 | IPv9 | April fools' day joke.[9] |
10-14 | Unassigned. | |
15 | Reserved. |
History
During the development of the first version of the Internet Protocol, in the seventies of the previous century, the initial experimental versions 1 to 3 were not standardized. The first working version that was widely deployed was assigned version number 4.[10]
A separate protocol based on reliable connections was developed, and assigned version 5.
IP version 7 was chosen in 1988 by R. Ullmann as the next IP version because he incorrectly assumed that version 6 was in use for ST-II. However, ST-II had reused version 5 of the original ST protocol.[5](p7)
When it became apparent, in the early nineties of the previous century, that IPv4 could not sustain routing in a growing Internet, several new Internet Protocols were proposed. The Internet Protocol that finally emerged was assigned version number 6, being the lowest free number greater than 4.
The PIP protocol and TUBA protocol used versions 8 and 9, following version 7 for TP/IX.
References
- Jon Postel, ed. (September 1981). INTERNET PROTOCOL - DARPA INTERNET PROGRAM - PROTOCOL SPECIFICATION. Internet Engineering Task Force. doi:10.17487/RFC0791. RFC 791. Updated by RFC 1349, RFC 2474, RFC 6864.
- S. Deering; R. Hinden (July 2017). Internet Protocol, Version 6 (IPv6) Specification. Internet Engineering Task Force. doi:10.17487/RFC8200. ISSN 2070-1721. STD 86. RFC 8200.
- Jeff Doyle; Jennifer Carroll (2006). Routing TCP/IP. 1 (2 ed.). Cisco Press. p. 8. ISBN 978-1-58705-202-6.
- L. Delgrossi; L. Berger, eds. (August 1995). Internet Stream Protocol Version 2 (ST2) Protocol Specification - Version ST2+. Network Working Group, Internet Engineering Task Force. doi:10.17487/RFC1819. RFC 1819. IEN 119. Status: Historic.
- R. Ullmann (June 1993). TP/IX: The Next Internet. Network Working Group, Internet Engineering Task Force. doi:10.17487/RFC1475. RFC 1475. Status: Historic.
- C. Pignataro; F. Gont (November 2012). Formally Deprecating Some IPv4 Options. Internet Engineering Task Force. doi:10.17487/RFC6814. RFC 6814.
- P. Francis (May 1994). Pip Near-term Architecture. Network Working Group, Internet Engineering Task Force. doi:10.17487/RFC1621. RFC 1621. Status: Historic.
- Ross Callon (June 1992). TCP and UDP with Bigger Addresses (TUBA), A Simple Proposal for Internet Addressing and Routing. Network Working Group, Internet Engineering Task Force. doi:10.17487/RFC1347. RFC 1347. Status: Historic.
- J. Onions (1 April 1994). A Historical Perspective On The Usage Of IP Version 9. Network Working Group, Internet Engineering Task Force. doi:10.17487/RFC1606. RFC 1606.
- Jon Postel, ed. (January 1980). DOD STANDARD - INTERNET PROTOCOL. Internet Engineering Task Force. doi:10.17487/RFC0760. RFC 760. IEN 128. Obsoleted by RFC 791.