IPv6 Network Administration

Chapter 2. The (Un)foreseen Successes of IPv4

If we want things to stay as they are, things will have to change.

Il Gattopardo, Giuseppe Tomasi di Lampedusa

Before we talk about how well-designed IPv6 (and how it fixes all the broken things in IPv4, honest!) it's worth pausing for a little bit to understand exactly what we can learn from the more successful elements of IPv4. These elements have informed and guided the design of IPv6, so it's worth examining in detail both the principles behind the design decisions, and the results of them. In many ways, the design of IPv6 can be said to have started when IPv4 was first created; so it, and we, will be beneficiaries of the hard work done and the lessons learned from over 20 years of deployment.

Simplicity

This first element is the most important consideration, and also quite a strange one. Initially you might think that simplicity was quite a philosophical or aesthetic principle, with no practical implications. Perhaps surprisingly, the opposite is actually the case; the desire for simplicity springs not solely from the human desire to create the elegant or the beautiful, but rather from sound engineering principles. The simpler a thing is, the easier it is to understand, the easier to control, the faster to operate, and the simpler to build upon. Put this way, simplicity in protocol design seems like such an obvious criterion, it's difficult to see who could argue for the opposite.^[1]

IPv4 itself was substantially simpler than its competition ...