IPv6 - a beginner's guide

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June 01, 2015

Colin Wallstleino,-June 01, 2015

The primary protocol used on the Internet is IP (Internet Protocol), which was developed in the 1970s. The version that has been used for many years is IPv4. The Internet has grown way beyond anything envisaged in those early days and with the advent of the Internet of Things (IoT), that rate of growth is not going to slow any time soon. It is unsurprising, therefore, that the original protocol is now rather stretched. Its address range is essentially exhausted and many of its ways of working are rather cumbersome. IPv6 was designed to address these and other issues. This article looks at the key features of IPv6 and the issues around its implementation in embedded systems.

IPv4 has been in use for well over 20 years and has proven to be amazingly adaptable over time. However, the demands placed upon the protocol at its inception pale in comparison to the demands of the millions of hosts that are now connected to the Internet. With IoT, there are likely to be billions of connected devices in just a few years. IPv6 deals with many of the shortcomings of IPv4 and introduces some new features. This paper discusses three of the major problems addressed by IPv6.

Limitations of IPv4
There are three primary shortcoming of IPv4:

  • depleted address space
  • flawed addressing architecture
  • high cost

 

Depleted Address Space
The main motivation for replacing IPv4 is exhaustion of available address space. Although an IPv4 address appears to be a 32-bit number, offering the possibility of 4 billion unique addresses, the address structure does not allow this potential capacity to be realized. A number of techniques have been used to “stretch” the capacity, but exhaustion is still inevitable.

Flawed Addressing Architecture
IPv4 addresses do not provide an efficient and scalable hierarchical address space; that is, it is impossible for a single high-level address to represent many lower level addresses or networks. To picture what a hierarchical address space looks like, think of the telephone numbering system. Just by looking at the area code, one can immediately determine what city or region to route the call to. It is not possible to look at a portion of an IPv4 address and make such a judgment. Therefore, routing becomes increasingly complicated and expensive as the size of the Internet grows.

High Cost
Another criticism of IPv4 is the high cost and maintenance requirements of networks. A significant percentage of the cost of administering an IPv4 network is incurred in the initial configuration of network hosts. IPv4’s limitations also aggravate the task of renumbering network devices, which is cumbersome to network administrators.

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Article page index:

  1. Introduction
  2. Introducing IPv6
  3. Under the hood -- Router discovery
  4. Under the hood -- DNS for IPv6


 

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