Because dotted decimal IP addresses are difficult to remember, TCP⁄IP also allows you to represent host interfaces on the network as alphabetic names, such as Alana.E04.IBM.COM, or CrFre@AOL.COM. Every Domain Name has an equivalent IP address or set of addresses. TCP/IP includes service functions (GETHOSTBYNAME and GETHOSTBYADDR) that will help you convert from one notation to another.