TABLE OF CONTENTS IPv6 embodies change in several important areas.
Expanded addressing
Simplified header format
Improved extension and option support
These changes to IP succeed at achieving most of the goals originally charted by the IAB back in 1991 (see RFC 1287, Toward the Future Internet Architecture ). The expanded IPv6 address space means IP can continue to grow without concern about depletion of resources; the addressing architecture helps improve the situation for routing efficiency.
The simplified header format improves routing efficiency by requiring less processing of packets, whereas the improvements in extension and option support mean that special needs can be accommodated without significantly affecting performance either of routing of normal packets or of the special-needs packets. Flow labeling provides another mechanism for treating streams of packets efficiently, particularly useful for real-time applications. Required support of IPsec, providing authentication and privacy, also makes IPv6 a more desirable protocol for commercial uses that require special treatment of sensitive information or resources.
The designers of IPv6 could have simply grafted a larger address space onto the existing IPv4 addressing architecture but doing so would cause us to miss out on a huge opportunity for improving IP. Changing the entire addressing architecture provides an incredible opportunity not only for improving efficiency of address allocation but also for improving IP routing performance.
The IPv4 address space was divided into several different classes based on the values of their high-order bits. The IPv6 address space is also...
