IPv6 Is an Evolutionary Step

This brief overview of IPv4 services was intended to remind the reader of the challenges and joys of designing and operating today's networks. It is not meant to be the background of an IPv6 sale pitch, but rather a frame of reference for the IPv6 discussion in this book. The overview offered us the opportunity to highlight, from a practical perspective, the differences between the two versions of IP and forward reference the chapters addressing these differences. If you remember only one thing from this chapter, remember that IPv6 is an evolutionary step in the development of IP communications. It is rooted in the fundamental concepts of IPv4, and it draws from IPv4's operational experiences. After years of dealing with IP networks, the addressing shortage gave us a chance to take another look at how things can be improved. Now that we know what to expect from the new protocol, we are ready to talk about its implementation and deployment.