Address pool
In the context of the Internet addressing structure, an address pool is a set of Internet Protocol addresses available at any level in the IP address allocation hierarchy. At the top level, the IP address pool is managed by the Internet Assigned Numbers Authority (IANA). The total IPv4 address pool contains 4294967296 (2) addresses, while the size of the IPv6 address pool is 2 (340282366920938463463374607431768211456) addresses.