IPv6 Essentials, 3rd Edition

Chapter 5. Networking

If you have read the previous chapters, you now know about the IPv6 basics, the new addressing architecture, the header format, and the Extension header architecture, as well as all about the new ICMPv6-based processes such as Neighbor Discovery (ND), Stateless Address Autoconfiguration (SLAAC), Path MTU Discovery, and Multicast Listener Discovery (MLD).

Before we dive into transition mechanisms and integration of IPv6 into the IPv4 network, this chapter covers several topics that are important in the network, such as Layer 2 support for IPv6, checksumming, multicast and how it has been extended for IPv6, available routing protocols, and quality of service. Last but not least, I discuss DHCPv6 and DNS. Even though IPv6 supports SLAAC, we expect DHCPv6 to be used in the enterprise networks, mainly due to the fact that organizations want to be able to log address use, which is not easily done if using SLAAC. And with the IPv6 address space coming into our networks in addition to still using IPv4, DNS becomes even more important than before.

Layer 2 Support for IPv6

IP sits between the Data Link layer and the Transport layer. One of the goals in the development of IPv6 was to be able to support as many different physical networks as possible and to require no changes in the Transport layer. This approach is called “IP over Everything.” To make IP as independent as possible from the Data Link layer, it needs an interface to this layer, which can be Ethernet, ATM, ...