Increasingly, enterprises that formerly shunned IPv6 are considering implementation or actively moving forward with it. IPv6 for Enterprise Networks brings together all the information network engineers and other professionals need to successfully deploy IPv6 in their campus, WAN/branch and data center environments. Four leading Cisco IPv6 experts show how IPv6 impacts existing network designs, describe common IPv4/IPv6 co-existence mechanisms, and guide network professionals in choosing the right implementation options for their environments. The authors begin by reviewing the drivers behind accelerating IPv6 deployment in the enterprise, and offering a refresher on IPv6 technology. Next, building on this foundation, they introduce powerful new IPv6 services for routing, QoS, multicast, security and management. These services are explained through parallels with familiar IPv4 features and behavior. Then, in Part II, the authors apply these concepts through concrete, usable configuration examples, including an end-to-end IPv6 network design case study.