IPv6 Enhancements in Windows 7

The TCP/IP networking stack in the Windows XP and Windows Server 2003 platforms had a dual-stack architecture that used separate network and framing layers for IPv4 and IPv6 based on separate drivers: Tcpip.sys and Tcpip6.sys. Only the transport and framing layers for IPv4 were installed by default, and adding support for IPv6 involved installing an additional IPv6 protocol feature through the Network Connections folder.

By contrast, in Windows 7, Windows Vista, and Windows Server 2008, the TCP/IP stack has been completely redesigned and now uses a dual-IP-layer architecture in which both IPv4 and IPv6 share common transport and framing layers. In addition, IPv6 is installed and enabled by default in these new platforms to provide out-of-the-box support for new features such as the Windows Meeting Space application, which uses only IPv6. Finally, the dual IP layer architecture means that all of the performance enhancements of the Next Generation TCP/IP stack that apply to IPv4 also apply to IPv6. These performance enhancements include Compound TCP, Receive Window Auto-Tuning, and other enhancements that can dramatically improve performance in high-latency, high-delay, and high-loss networking environments.