assignment of network blocks,
assignment of network blocks, is deemed sufficient for the foreseeable future. Mathematically, the new address space provides the potential for a maximum of 2128, or about 3.403×1038 addresses. The primary intent of the new design is not to provide just a sufficient uantity of addresses, but rather to allow an efficient aggregation of subnetwork routing prefixes at routing nodes. As a result, routing table sizes are smaller, and the smallest possible individual allocation is a subnet for 264 hosts, which is the square of the size of the entire
IPv4 Internet. At these levels, actual address utilization rates will be small on any IPv6 network segment. The new design also provides the opportunity to separate the addressing infrastructure of a network segment, that is the local administration of the segment's available space, from the addressing prefix used to route external traffic for a network. IPv6 has facilities that automatically change the routing prefix of entire networks, should the global connectivity or the routing policy change, without requiring internal redesign or manual renumbering. The large number of IPv6 addresses allows large blocks to be assigned for specific purposes and, where appropriate, to be aggregated for efficient routing. With a large address space, there is no need to have complex address conservation methods as used in CIDR.