Section 1.2. What s New in IPv6?

1.2. What's New in IPv6?

IPv6 is an evolution of IPv4. The protocol is installed as a software upgrade in most devices and operating systems. If you buy up-to-date hardware and operating systems, IPv6 is usually supported and needs only activation or configuration. Currently available transition mechanisms allow the step-by-step introduction of IPv6 without putting the current IPv4 infrastructure at risk.

Here is an overview of the main changes:

Extended address space

The address format is extended from 32 bits to 128 bits. This provides an IP address for every grain of sand on the planet. In addition, it also allows for hierarchical structuring of the address space in favor of optimized global routing.


Perhaps the most intriguing new feature of IPv6 is its Stateless autoconfiguration mechanism. When a booting device in the IPv6 world comes up and asks for its network prefix, it can get one or more network prefixes from an IPv6 router on its link. Using this prefix information, it can autoconfigure for one or more valid global IP addresses by using either its MAC identifier or a private random number to build a unique IP address. In the IPv4 world, we have to assign a unique IP address to every device, either by manual configuration or by using DHCP. Stateless autoconfiguration should make the lives of network managers easier and save substantial cost in maintaining IP networks. Furthermore, if we imagine the number of devices we may have in our homes in the future that will need an IP address, this feature becomes indispensable. Imagine reconfiguring your DHCP server at home when you buy a new television! Stateless autoconfiguration also allows for easy connection of mobile devices, such as a mobile phone or handheld, when moving to foreign networks.

Simplification of header format

The IPv6 header is much simpler than the IPv4 header and has a fixed length of 40 bytes. This allows for faster processing. It basically accommodates two times 16 bytes for the Source and Destination address and only 8 bytes for general header information.

Improved support for options and extensions

IPv4 integrates options in the base header, whereas IPv6 carries options in so-called extension headers , which are inserted only if they're needed. Again, this allows for faster processing of packets. The base specification describes a set of six extension headers, including headers for routing, Mobile IPv6, and quality of service and security.

IPv6 Essentials
IPv6 Essentials
ISBN: 0596100582
EAN: 2147483647
Year: 2004
Pages: 156
Authors: Silvia Hagen

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