The 128-bit IPv6 address consists roughly from 2x64 bit blocks where the first 64-bit block indicates the type of address and provides geographical information. This part also identifies the ISP or large organisations that have large IP blocks in use. ISP's on their turn assign IP address blocks to their end-users being smaller organisations or home users.
The second 64-bit block is solely used for addressing individual interfaces.
The RIPE IPv6 Allocation Policy states the following: "End Users are assigned an End Site assignment from their LIR or ISP. The size of the assignment is a local decision for the LIR or ISP to make, using a minimum value of a /64 (only one subnet is anticipated for the End Site)."
Some numbers: Some time ago my home ISP enabled native IPv6 on my ADSL connection. I was surprised when they assigned me, as a home user, a very generous /48 IPv6 address which I can use any way I like.
With this space I am able to connect 2^(128-48) = 1.208.925.819.614.629.174.706.176 publicly addressable devices or interfaces to my private internet connection... Wow! This is insane.. I could now build the equivalent of 2^80/2^32 = 281.474.976.710.656 complete IPv4 internets.. at home.. or I could use the 16-bit Site Identifier part to create 2^16 = 65.536 subnets where in each of them I would be able to connect 2^64 = 18.446.744.073.709.551.616 devices.
To avoid dazzling you even more, I leave the possibility of using the 2^64 locally addressable space alone. These are phenomenal numbers.. especially considering the fact that currently I only have about 10 addressable devices in my home to play with. Indeed, this IPv6 allocation policy seems to be an enormous waste and a complete overkill.
Many of our customers are looking at IPv6 because they are forced by authorities, legislation, they want to avoid losing market share by keeping communication with their Asian partners possible, avoiding technology lag or just because they already face an IPv4 shortage in their IT environment. With our help, they investigate IPv6 adoption in their current or future IT environment by performing risk and opportunity assessments, implementing awareness programs and creating migration plans.
For most of these organizations with multiple sites, business units and departments a /48 would be more than sufficient. When using IP in the traditional way, their usage of addresses can be compared with taking a teaspoon of sand from the beach that is available to them. IPv6 "consumption" will be boosted when organizations start to fully use the potential of Machine to Machine (M2M) and "Internet of Things" applications which will use countless addressable sensors and devices, production and logistics processes that can be managed and controlled.
IPv6 can even be considered to be "Green" when, for example, street lights are able to be individually switched off and on, or even dimmed depending on the IP addressable traffic sensors on every road in the country or IPv6-enabled GPS location chips in each vehicle. Of course, this is what the upgrade to IPv6 is all about: the possibility to connect everything to anything in order to enable measurement and control.
Back to the private environment; I am still wondering why a home internet connection would need so many IP addresses and why the inventors of IPv6 made the type/geographic part (first 64 bits) and the second 64-bit interface part equal in size. You would expect that if the geographic part would be bigger, let's say /96, and the home user would get a /32 address space as it would be more than sufficient. The amount of IP addresses a home user gets now depends on the generosity of the ISP, where given address space ranges vary from a generous /48 and a stingy /64.
Even in case of an economical ISP that assigns the minimum of a /64 bit IP address to their home subscribers, you might think that the waste is enormous. Those couple of sensors for measuring my home utility services or the sensor in my refrigerator that automatically orders some more beer at the super market when stock is low, will not fill my address space. Applications are already available for a fully domestic home control system where security cameras, automatic lighting, audio and video systems, heating, solar and energy saving systems can be managed via the internet (or by hooking up my poor cat to the Internet with a GPS chip and camera so anyone could follow him exploring the neighborhood).
No, all those current or near future applications will only take one drop from the ocean of IP addresses I have now... I need to be more creative and innovative to find out if the current IPv6 allocation policy is that wastful. Which future applications are going to take up my IP space and will all those applications be available before we move to IPv7, which may have even more address space? It is great to read and brainstorm about this.
It is nice to know that with the current IPv6 space available I can individually control the soldiers in my future nano bot army from the internet. I do not know what my nano bots will be doing yet, perhaps I can use them as full color HD pixels in paint in order to re-decorate everything in my home or my car with a push on the button. Perhaps I can stay under water as long as I want because the nano bots in my blood vessels will provide me with the necessary oxygen. All remotely controlled from the internet of course.. With individually controlled nano bots in my face muscles I can also straighten my face again removing the wrinkles caused by the grin on my face thinking about all these applications...
Marcel is a Managing Consultant, CISSP-ISSAP and ISO27K Lead Auditor certified. Specialised in IT Security and Unified Communications at Orange Business Services in Amsterdam since 1998. Marcel has more than 28 years experience in the Electronics, Offshore and the IT industry where he fulfilled roles in Electronic Engineering, Project Management, Operational Management, Quality Management, Managed Security development, Compliancy and Consultancy Risk Assessments.