Intro to IPv6

Anthony Borgert's Summer Project CNT 2453-01

This tutorial is aimed at developing a basic understanding of IPv6 for the new user. The reason IPv6 was created was because of an explosive increase in the number of devices requiring an IP address to communicate on a network and the depleting resources of IPv4 address space. Current estimates suggest that by 2011, all of the left over addresses will be used up; meaning anyone not already connected to the Internet risks being left behind. Born out of necessity IPv6 is a solution to this problem, made up of a suite of protocols and standards that where developed by the Internet Engineering Task Force (IETF). Not only does IPv6 increase address space but it also solves problems discovered with IPv4 that became evident over the years. Deploying IPv6 on a global scale is vital to the Internet industry.

General IPv6

The main difference between IPv4 and IPv6 is where IPv4 addresses consist of 32 bits, IPv6 addresses consist of eight blocks of 4 hexadecimal digits each. Four hexadecimal digits are equal to 16 bits, so an IPv6 address has 8*16 = 128 bits.

• An example of an IPv6 address looks like this: 2001:4CEA:8D8C:0000:0000:0000:00D2:7A4B

From this example it is apparent to anyone that IPv6 addresses are more complex to remember than IPv4 addresses. Therefore some rules have been developed to shorten addresses to something more manageable.

Address Structure Rules

Any leading digit of Zero can be dropped from any group

• The example above will look like this with this rule: 2001:4CEA:8D8C:0:0:0:D2:7A4B

Two or more groups of zeros can be replaced by two colons, (But only once per address).

• Then it looks like this: 2001:4CEA:8D8C::D2:7A4B

This is much simpler.

Types of IPv6 addresses

There are three main types of IPv4 addresses (APIPA, Private, and Public)? The same is true for IPv6, only they have different names:

• Global Address (GA): this is the equivalent of IPv4’s (public address). These addresses start with a first block in the 2000-3FFF range.

• Link-Local Address (LLA): this is the equivalent of the IPv4 (APIPA address). These addresses always start with "fe80".

• Unique Local Address (ULA): this is the equivalent of IPv4’s (private address). Where IPv4 private addresses fall within three ranges, ULA’s always start with "fd".

There are two more that have more specific uses:

• Multicast address: these addresses are reserved for multicast communications.

• Special address: these are reserved addresses for specific usage.

Some features that are available only in IPv6 are:

Stateless address autoconfiguration - lets hosts configure themselves automatically.