IP-telephony has been presented as a technology which can replace existing fixed-line services and disrupt the telecommunications industry by offering new low priced services. This study investigates the diffusion of IP-telephony in Denmark by focusing on vendors’ commercialisation strategies. The theory of disruptive innovation is introduced to investigate vendors’ perceptions about IP telepho...

Security as a dimension of trustworthiness in IP-Telephony systems and protocols is a main condition for the commercial success of IP-Telephony. In this work, we present a survey of security requirements and show how various standardization efforts address these requirements. We describe the basic tasks and elements of IP-Telephony systems and compare them to Telephony via PSTNs to derive some ...

IP telephony presents some big advantages over traditional circuit-switched telephony especially in the sense of increased utilization of expensive backbones and significantly reduced cost. However, in order to win the competition, IP telephony must provide the same quality of voice service as the traditional telephony, which has been proven as a major challenge. In today’s VoIP market, multipl...

Successful deployment of networked multimedia applications such as IP Telephony depends on the performance of the underlying data network. QoS requirements of these applications are different from those of traditional data applications. For example, while IP Telephony is very sensitive to delay and jitter, traditional data applications are more tolerant of these performance metrics. Consequentl...

With the introduction of IP based telephony services, the Internet has started to challenge the traditional PSTN networks as an infrastructure for providing real-time interactive services. This upcoming paradigm shift is not only driven by the desire to provide cost efficient solutions, but by basing the communication on IP we expect that the end-users will experience a greater set of attractiv...

From the angle of competition policy, Voice over IP looks like a panacea. It not only brings better service, but it also increases competitive pressure on former telecommunications monopolists. This paper points to the largely overlooked downside. In a pure world of Internet telephony, there would be no charge for individual calls, nor for telephony, as distinct from other services running over...

Real-time applications such as IP Telephony demand strict quality of service (QoS) from the underlying network. As more enterprises deploy IP Telephony, it is becoming imperative to significantly improve the network reliability as seen by these applications. As such, we recently proposed a practical overlay architecture, ORBIT (Overlays providing Reliability for Better IP Telephony). Our archit...