Wireless Voice over IP

摘要

This paper discusses the convergence of mobile, wireless, and voice over Internet protocol (VoIP) technologies. It is intended for those interested in the convergence of VoIP and wireless technologies. The question of "What is VoIP?" is easy to answer technically: it is transmitting digitized voice over packet-based IP networks. Clearly stating the various modes, contexts, and uses of VoIP is not nearly as easy. One view of VoIP is that it is just another Internet application, like the Web, e-mail, instant messaging, or file transfer protocol (FTP). This is the view taken by voice-enabled instant-messaging programs, like Apple's iChat AV, and peer-to-peer VoIP applications like Skype. This is potentially the most disruptive view of VoIP but also the one that is most in the future. The purest version of this does away completely with the public switched telephone network (PSTN), but doing that is impractical today. Even pioneer Skype introduced SkypeOut to provide its users with a PSTN gateway during a follow-up service launch.