Internet的飞速发展为IP语音技术提供广阔的发展空间,而价格更低廉、技术更加开放的IP语音技术又为运营商和用户提供了更多的增值业务及新型服务。全球的电信行业正在发生着巨大的变革,当各种数据业务量象潮水一样淹没了传统的话音业务时,现有的话音网络已经显得力不从心。在电信运营商力图降低成本、获得更多增值服务以及用户希 The rapid development of the Internet provides a vast space for development of IP voice technology. The cheaper and more open IP voice technology provides more value-added services and new services for operators and users. The global telecoms industry is undergoing dramatic changes, and existing voice networks are out of power as various data services flood the traditional voice business like a flood of water. Telecommunication operators in an attempt to reduce costs, access to more value-added services and users hope