Why IPv6?
Two good reasons to move to IPv6 are as follows:
IPv6 has more address space available.
We are running out of public IPv4 addresses.
For more than a decade, the requirement to implement IPv6 has been threatened as imminent. The lifetime of its predecessor (IPv4) was extended more than a decade because of features such as Network Address Translation (NAT), which enables you to hide thousands of users with private IP addresses behind a single public IP address.
With IPv6, upper-layer applications still work like you are used to with IPv4. The biggest change is that we are doing a forklift upgrade to Layer 3 of the OSI model. Along with this change, there are some modifications as to how IPv6 interacts with the rest of the protocol stack and some modifications to its procedures for participating on the network.
Table 12-2 describes a few of the notable differences and some similarities between IPv4 and IPv6.
