
Chapter 9 • IPv6 Options and Extension Headers 181
9.5 Summary
Although IPv4 options have been defined from the very beginning, their
use has never been widespread. IPv6 option header extensions have been
designed to remedy the flaws in IPv4 options, and, as demonstrated in
this chapter, should gain wider acceptance. Although so far only a few
options have been defined, they may be applied in a number of different
ways to enable protocol tunneling, routing options, security options,
fragmentation, and more.
As we’ll see in Chapter 17, the IPv6 mobility protocol uses an extension
header, but in the next chapter we examine another function—multicast—
that, ...