A short introduction to IPv6

In September 2015, I published an article on LinkedIn about IPv6 because ARIN announced that they had exhausted their IPv4 address space! I think that we will, finally, see a lot of enterprises adopting IPv6.

The North American organization is now only able to deliver very small chunks of IPv4 addresses to help in transitioning from IPv4 to IPv6.
First of all, IPv6 is not a new protocol. IETF has been working on it since the 1990s.
IPv4 is (was?) a 32-bit address space, with a lot of unusable IP addresses (Test, Multicast, Reserved for “Future Use”, Network address, Subnetting, …). The theoretical maximum number of addresses is 2^32 (4,294,967,296). In IPv6, the maximum number of addresses is 2^128 (340,282,366,920,938,463,463,374,607,431,768,211,456 or 3.4×10^39).
Most modern systems are able to run dual stack (IPv4 and IPv6), as are most modern applications.
While IPv6 is still IP in the payload and the general behaviour, the way to use, route and allocate addresses is totally different from IPv4.
First of all, about address allocation. The system administrator should be able to forget everything he knows about IPv4 address allocation. In IPv6, you NEVER subnet in less than /64 networks (I wrote NEVER, this is NEVER). This is the most difficult part for Net and Sys admins. They must learn a new way of thinking. The idea behind this is to give a public IP address to all connected devices (nice for IoT).
The general routing protocol between ISPs is still BGPv4, but if you were using OSPFv2 for internal routing, you’ll have to use OSPFv3 from now on.
The way the headers are organised in IPv6 reduces the load on routers.
Quality of service and Security were also built into the protocol from the beginning. In fact, IPsec was defined for IPv6.
There are working, standardised discovery and autoconfiguration protocols to help the administrator set up his basic IPv6 network.
So a tight integration with your DNS will be mandatory, as 128 bits of IP addresses makes it impossible to learn/remember all your important device IP addresses the way you (probably) did with IPv4. Therefore, a good, working DNS infrastructure will be needed.

If I see that there is interest in this short introduction, I’ll give a more detailed look at the working internals of IPv6 for SYS and NET admins!
You can also find a lot of information at http://ipv6actnow.com.

Pascal Fuks has achieved the HE certification of “IPv6 Sage” while managing to drive his former company, Financial Art, to 4 stars in the RIPE classification for companies implementing IPv6.