Networking Fundamentals

Subnets and prefixes

Just like IPv4, IPv6 addresses use a similar concept of subnetting. However, we do not use the dotted decimal notation. Instead, we use the slash notation we used in CIDR, and this is referred to as a prefix. Like CIDR, the notation refers to how many bits of an IPv6 address the network element uses. The remainder, like IPv4, is set aside for the host element.

The term prefix is used here as it refers to the bits at the start of the IP address indicating the network element. Fortunately, the MTA exam does not interrogate you much on IPv6 subnets and prefixes—at least not to the same degree as it does for IPv4. As we go through the various addresses, it will be sufficient just to know what prefixes go with what address ...