NWA-PCUG Newsletter Article, August 2011
IPv6 is Coming
By Cal Esneault,
President and leader of many Open Source Workshops & SIGs,
Cajun Clickers Computer Club, Louisiana ,
April 2011 issue, Cajun Clickers Computer News
cjesne (at) bellsouth.net (click to email author)

Canonical (Ubuntu Linux) and Google recently announced they would participate in a 24-hour trial of IPv6 on June 8, 2011, along with Facebook, Yahoo, and others. This means that some of the big names in open source software will be involved with the new Internet Protocol, version 6 (IPv6) which will be needed to replace the current Internet Protocol, version 4 (IPv4).

To get to an Internet address, we usually type in a name, such as Clickers.org or Google.com. Software then goes to a distributed database from a Domain Name Server (DNS) and uses a table to translate this into a 32-bit numerical identifier. The identifiers are split into four 8bit segments. Since 8 binary digits (bits) can span the range from 0 – 255, we sometimes see these addresses as the decimal equivalents separated by periods. For example, is a typical address for our internal networks when using routers. If we use the last “block” (last 8 bits), we could theoretically have 256 computers in this network. The total number of distinct addresses in IPv4 is 256 x 256 x 256 x256 = 4.3 billion. When the Internet first started, no one could conceive that more than 4 billion addresses would be needed, but the need for each home network and each mobile phone to have an address is straining that concept. Recently, the last big “blocks” were issued to area centers for distribution. The problem is not as bleak as it may seem since many addresses can be issued temporarily, some early users took more than they really need and can give some back, and only one address is needed for a private network which handles many computers within its structure. Some believe that we will run out of freely available addresses by the end of 2011, and that new addresses will have to wait for an old one to be freed up.

Internet designers have been working on the new IPv6 protocol to solve issues with the old system. It will have 128-bit addresses which will provide for a possible of 340 trillion, trillion, trillion addresses (3.4 x 10^38). This at first seems silly today since each person on earth could have trillions of addresses, but it becomes more reasonable when you realize that any electronic device in your home (which will soon be a computer) and any device in a factory or automobile could have a unique address for control purposes. Also, it is hoped this will be sufficient for a very long time so that the change will be permanent in even our grandchildren's lifetimes.

The addresses for IPv6 will be split into eight 16-bit units. Since the decimal number for each unit is large (2^16 = 65,536), the addresses will be in hexadecimal notation (a = 10, b = 11, … , f =15). An example address might look like fe80:0:0::200:f8ff:fe21:67cf where fields are separated by a colon, leading zero's can be omitted, and blank fields can be represented by multiple colon marks. There will be a protocol which allows current IPv4 addresses to be contained within the new IPv6 address. If all works as hoped, we won't care since our DNS resources will fill in numbers for us when we type in Clickers.org, etc., just like it happens today.

Modern operating systems (Windows, Mac OS, Linux, BSD) have already been configured to allow for IPv6 protocol. However, your current router and your ISP (Internet Service Provider) equipment may not be ready. In complex computer networks, all of the interactions between equipment and older software are not sufficiently known. Therefore, the test on June 8 will be the first of probably many to debug the issues which will have to be addressed. A similar situation was envisioned when we moved into the 21st century (known as the Y2K issue, where ambiguity between dates could occur since early software only used the last two numbers for years).

In that case, the situation was handled well and none of the dire predictions about airplane crashes and business shutdown came to pass. It did, however, take a lot of work and effort to prevent chaos. Will IPv6 be a big event, or just a problem for computer professionals? We don't know yet, but open source folks are in there with everyone else to help keep our systems functioning.

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