A dynamic IP addressing system for Internet telephony applications

For Internet telephony systems, it is necessary to establish a connection between a caller and recipient using the Internet Protocol (IP) address before actual voice communication can take place. A problem of dynamic IP addressing arises when the connection to the Internet is made through an Internet Service Provider (ISP) since the IP address is dynamically allocated only at connection time. This paper discusses a dynamic IP addressing system to support the establishment of connections between users. A number of dynamic IP addressing methods that are classified as on-line methods, namely, WorldWide-Web approach, Exchange Server and Dynamic Domain Name System, or off-line methods, namely, Electronic Mail and Directory Service Lookup, are proposed, implemented and contrasted.