Background
TCP and UDP are the protocols on which all Internet applications
depend. TCP and UDP, in turn, depend on IP. IP is the glue that joins
the world's diverse collection of hosts, LANs and WANs into a single
big virtual network. Without IP, the Internet as we know it would not
exist.
Every machine that connects to the Internet must have a unique
address. The current version if IP, version 4, uses 32-bit
addresses. In theory, 32 bits results in many addresses (over 4
billion), but in practice only a fraction of the addresses can be
used. The Internet is growing exponentially. In January 1993 there
were an estimated 1.3 million machines; by January 1996, the number
had reached 9.5 million [Reference]. There is
widespread agreement within the Internet community that the Internet
will run out of addresses early in the next century. The debate is not
if, but when.
IP Version 6
IP Version 6 (IPv6) is the specific protocol chosen by the IETF as the
Internet's Next-Generation IP. IPv6 uses 128-bit addresses, to insure
sufficient addresses to last well into the 21st Century and beyond.
Given that IP had to change to accomodate bigger addresses, the IPv6
standardization effort also extends and improves on known limitations
of IPv4. Specifically, IPv6 has the following advantages:
- Essentially unlimited address space
- Simplified autoconfiguration; machines can plug into a network,
generate their own addresses without manual configuration, and gain
full Internet access
- IPv6 header is designed for optimized processing
- Standard set of security features all IPv6 nodes must implement
- Native multicast support
- Support to automatically renumber entire networks
Status of IPv6
The specifications for the core pieces IPv6 protocols have been issued
as Proposed Standards by the IETF, and all major vendors (host and
router) are known to be doing IPv6 implementations. Indeed, the UNH Interoperability Lab hosted
IPv6 "testathons" in February and June of 1996 for vendors to test out
there implementations. Sun, HP, Digital, IBM (AIX), Bay Networks and
Ipsilon have participated. Both Sun and Digital have prototype
implementations that folks can download from the Internet for testing
purposes. More information on implementations can be found
here
For More Information
For information on the official current status of IPv6, the various
draft documents the WG is developing, pointers to the mailing list
(and its archives), etc., visit the IETF's official
IPng Working Group page. Another good collection of semi-official
material can be found at the playground
archive, which is maintained by one of the IPng WG
co-chairs.
For background on the issues that lead to the decision to chose IPv6
as the next standard, consult RFC 1752 and its
extensive set of references. The book "IPng Internet Protocol Next
Generation" (S. Bradner, A. Mankin editors, 1995. (ISBN 0-201-63395-7)
contains similar information, but edited and distilled for easier
reading.
If you think it's about time you learned something about IPv6, but
don't know where to start, there is already at least one book on IPv6
that delves into the technical detail of the protocols: "IPv6 The New
Internet Protocol" (Christian Huitema, 188pp., 1995. ISBN
0-13-241936).
If you would rather go straight to the RFCs, I'd suggest starting with
the following (in approximate priority order).
- "Internet Protocol, Version 6 (IPv6) Specification",
S. Deering, R. Hinden, RFC 1883,
01/04/1996.
- "IP Version 6 Addressing Architecture", R. Hinden,
S. Deering, RFC 1884, 01/04/1996.
- "Neighbor Discovery for IP Version 6 (IPv6)", T. Narten,
E. Nordmark, W. A. Simpson, Internet Draft (Approved as Proposed
Standard by IESG, awaiting publication as an RFC) draft-ietf-ipngwg-discovery-04.txt.
- "IPv6 Stateless Address Autoconfiguration", S. Thompson, T. Narten,
Internet Draft (Approved as Proposed Standard by IESG, awaiting
publication as an RFC) .
draft-ietf-addrconf-ipv6-auto-07.txt.