Understand why we need IPv6. Without IPv6, the world would be depleted of IP addresses.
Understand link-local. Link-local is like an IPv4 private IP address, but it can’t be routed at all, not even in your organization.
Understand unique local. This, like link-local, is like a private IP address in IPv4 and cannot be routed to the Internet. However, the difference between link-local and unique local is that unique local can be routed within your organization or company.
Remember IPv6 addressing. IPv6 addressing is not like IPv4 addressing. IPv6 addressing has much more address space and is 128 bits long, and represented in hexadecimal, unlike IPv4, which is only 32 bits long and represented in decimal.