y required in networks, based on the type of applications that carriers and service providers are supporting. In terms of U.S. domestic policy, the U.S. government endorses moving forward with ENUM based on the concept of an industry management limited liability corporation similar to that used with number portability. It involves an arm's-length contractual relationship with an administrative entity. This is similar to existing relationships with ICANN (www.icann.org) for IP address space, top-level domain names, and root server man- agement; with NeuStar (www.neustar.com) for numbering plan and portability man- agement; and with VeriSign (www.verisign.com) for .com and .net registries. The U.S. ENUM Forum (www.enumf.org) is developing policies and taking steps to implement ENUM in the United States. Some early participants include AT&T, Sprint, SBC, Verizon, Neustar, Cox Cable & Wireless, Cisco, and Telcordia. However, it is anticipated that it will be a while before the United States sees public ENUM. Several national forums are under way in the United Kingdom, Austria, Sweden, Japan, the Netherlands, Germany, Brazil, Austria, Poland, and elsewhere. A number of resources are available on the Web, including the approved ENUM delegation list (www.ripe.net/enum/request-archives) and the ITU ENUM Web page (www.itu.int/osg/spu/enum/index.html). IPTV is generally described as a system that delivers digital television service to a subscriber using IP over a broadband connection, often provided in conjunction with video-on-demand (VOD), Internet services, and VoIP, as part of triple-play ser- vices (a combination of voice, data, and video services over the same infrastruc- ture). In its simplest definition, IPTV is the delivery of television content through technologies used for the World Wide Web rather than traditional formats. Some say that incumbent telcos have developed their current interest in offer- ing video or TV services as a result of fear-fear that cable operators are beginning to encroach on their territ