updated 02:10 am EDT, Fri June 8, 2012
Increased internet efficiency, static device IP expected
After years of preparations, the IPv6 communications protocol is live, worldwide. While the IPv4 and IPv6 protocols will have to run in parallel for some time -- using bridging technologies to ensure that one side can reach the other, the foundation has been laid for the future of the Internet. The various issuing bodies are running out of IPv4 addresses -- there are 4.2 billion possible combinations addressable with the current system. IPv6 allows for 3.4 x 10^38 (10 to the 38th power) addresses, accommodating more devices and users on the Internet as well as providing for greater flexibility in address allocation and Internet routing efficiency.
IPv4, the current system, was the first publicly-used Internet protocol, and was never intended for widespread use. When Vint Cerf and the fellow researchers at ARPA (now DARPA) ran testing in the early '80s to prove the viability of the technology, an executive decision was made to demonstrate a 32-bit addressing system to cease engineers squabbling with no end in sight. The addressing system "escaped," was made commercial, and became the de facto standard. By the late '80s, it was apparent that the system would ultimately have to be redesigned to accommodate for more addresses and devices.
In 1996, a group of 15 engineers had selected a new standard -- IPv6. In the beginning of this century, opinions varied on how long the IPv4 pool of addresses would last. In 2005, Cisco systems anticipated that the pool of remaining addresses would deplete in as little as 4 years. In fact, the last of the IPv4 addresses are being doled out to providers now, and IPv4 depletion is happening a bit slower than originally anticipated, but not so slowly that a replacement doesn't need to be in place.
IPv4 addresses are the frequently-seen four groups of three hexadecimal digits separated by decimal points (192.168.0.1). IPv6 addresses are written in eight groups of four hexadecimal digits separated by colons, with the first half being the network or subnetwork prefix, and the last half being the device identifier (1234:5678:90AB:CDEF:1234:5678:90AB:CDEF). A field of four zeroes can be abbreviated with a single zero, and the universal protocol for shortening textual display of IP addresses is still being negotiated.
The 128-bit address space of IPv6 simplifies allocation of addresses. The packet architecture, or smallest quanta of data sendable in a single event, is more efficiently structured, allowing for more efficient routing across the Internet. If needed, very large packets can be sent, up to 4GB per packet, increasing efficiency in much the same way that a hard drive can be formatted for larger block size if it is expected to be holding larger files, versus lots of smaller ones. IPv6 routers will never fragment a packet by design.
Current ISP implementation of IPv4 doesn't allow for global unique IP addresses. A more advanced form of network address translation (NAT) as found in a home router is used at the ISP network level to dole out IP addresses to customers. IPv6 as specified has 4.8 x 10^28 IP addresses for each of the seven billion inhabitants of this planet. Every device ever created can have a unique Internet-facing IP address, which facilitates ease of device tracking. Privacy extensions for IPv6 have been pre-defined to address these concerns, in the form of a rudimentary proxy -- a randomly generated host identified with the assigned network prefix. In essence, the network prefix, or first couple of octets in the IPv6 address is static, and the remainder of the connecting IP is random. This doesn't prevent cookie installation from web surfing or other user-based breaches of privacy settings, however.
Until IPv4 is completely retired, various technologies are being used to ensure network interoperability. A dual stack, with a packet containing both IPv4 and IPv6 addresses is the primary method of connectivity right now, but this reduces the IPv6 functionality and inherent efficiency of the protocol. Other methods such as various forms of network tunneling can be implemented as well, but as of yet, there is no standard. As time goes on, and the IPv4 addresses are completely issued, more and more devices will only have IPv6 functionality, making interoperability more and more irrelevant.
For users, IPv6 compatibility is a software or firmware issue, primarily. DOCSIS 3.0 cable modems are fully compatible, as are most modern routers and commercial network switches manufactured in the last 12 years. Some legacy equipment, such as industrial controllers, printers, and some Voice over Internet Protocol equipment may not be updated, and will have to rely on external support or routing to continue functioning in an IPv6-only world.
Many network providers in the Pacific Rim are out of IPv4 addresses, and won't be receiving any more, so the IPv6 migration for them is effectively complete by default and eradication of IPv4 is just a matter of time. There is no official timetable for full migration to IPv6, so how long it will take western nations to move is undetermined.