In spite of all the technological progress, VoIP, IM, presence, and multimedia services are still a highly fragmented industry
Telephone services based on VoIP operate as islands and can interconnect (as of this writing) using mostly the legacy Public Switched Telephone Network (PSTN). The service model is giving broadband users Introduction xxvii access to the legacy telephone system, actually a voice gateway service between the Internet and TDM.
The business model of most VoIP service providers is just lower cost for legacy-style telephone service, also called PSTN over IP. The PSTN gateway services are using IP inside their networks, but users are not exposed to the rich IP services, except when all parties are on the same network.
- The most successful public voice, IM, and presence service is Skype, which is not standards-based.
- Walled gardens: The fragmentation of communications is still actively pursued by most mobile service providers by deploying systems where their users can get rich IP multimedia services only on their own networks. The fees to communicate between mobile service providers are a significant part of the business model, and open connectivity to the Internet (“Internet neutrality”) is still a hotly debated issue. Internet neutrality is also still debated by many broadband Internet access providers (such as DSL and cable companies), although we believe that enlightened government regulators in the developed countries will weigh in favor of users and open network access in general.
The proliferation of islands for communications makes them less useful the more there are, since this proliferation is in denial of Metcalf’s law that the value of a network increases with the square of the number of points attached to the network. The Internet with more than 1 billion attached endpoints has thus the highest value for communications. By contrast, the mobile phone industry boasts 3 billion users, but in many fragmented networks.
Past Obsessions and Present Dangers: QoS and Security
Network-based quality of service (QoS) for voice and the reliability of the legacy telephone network have long been used by telephone industry marketers to scare users away from VoIP. In the meantime, all public VoIP services have proven that Internet best-effort QoS works just fine, as long network congestion is avoided. Internet-based voice can actually be much better than the 3.1 kHz voice over the PSTN. As for reliability, all recent major man-made and natural disasters have proven the Internet and VoIP to be more resilient than the existing wireline and wireless telephone networks
The security threats on the Internet have provided well-justified concerns about the security of VoIP, and even more, the security of IM. As a result, a new industry niche, that of VoIP and IM security, has sprung up and, as usual, marketers are first drumming up the vulnerabilities of Internet communications to prepare the sell for all kinds of security products. Though no significant security breaks have been reported so far for Internet communications, security for VoIP and IM is still work in progress. Chapter 9, “SIP Security,” deals with SIP security.