The protocol definition of IPv6 was developed some years ago, but the deployment in real-world networks is a long time coming. The reasons are manifold - the exhaustion of the IPv4 address space has not occured yet and the practical use of IPv6 is a big question mark. But at some point network engineers will have to deal with the new protocol in their environments. The author Florian Frotzler provides an introduction on the IPv6 protocol, several interworking strategies between IPv4 and IPv6 and large scale international projects that deal with the implementation of the new protocol. Based on the Test Traffic Measurement Service (TTM) from RIPE-NCC, an internationally distributed one-way-delay testing facility, futher analysis of the quality of the European IPv6 backbone are presented that give an insight on routing stability and connection quality in comparison to IPv4. The book is aimed at engineers working in academic networks and networking engineers in general.