It is useful to preserve and extend the interpretation of these special addresses in subnetted networks.

^ Jeffrey Mogul Jon Postel (August 1985).

the last subnet, known as the all-ones subnet ^ 'Document ID 13711 - Subnet Zero and the All-Ones Subnet'.Today, the use of subnet zero and the all-ones subnet is generally accepted and most vendors support their use. Traditionally, it was strongly recommended that subnet zero and the all-ones subnet not be used for addressing. IPv6 Subnet Model: The Relationship between Links and Subnet Prefixes. Neighbor Discovery for IP version 6 (IPv6). Requirements for Internet Hosts - Communication Layers. Classless Inter-domain Routing (CIDR): The Internet Address Assignment and Aggregation Plan. Another common allocation size for residential customer networks has a 64-bit prefix. However, this recommendation was revised to encourage smaller blocks, for example using 56-bit prefixes. In the past, the recommended allocation for an IPv6 customer site was an address space with a 48-bit ( / 48) prefix. The host identifier is a unique local identification and is either a host number on the local network or an interface identifier. The number of bits allocated within a network to the prefix may vary between subnets, depending on the network architecture. This prefix occupies the most-significant bits of the address. All hosts on a subnetwork have the same network prefix. An IPv6 address consists of 128 bits written in a hexadecimal notation and groupings of 16 bits, called hextets, separated by colons.An IP address is divided into two logical parts, the network prefix and the host identifier. An IPv4 address consists of 32 bits, for readability written in a form consisting of four decimal octets separated by dots, called dot-decimal notation. The most common network addressing architecture is Internet Protocol version 4 (IPv4), but its successor, IPv6, has been increasingly deployed since approximately 2006. An address fulfills the functions of identifying the host and locating it on the network.

Acs560 hardware manual