Voice networks evolved from the fixed traditional telephone system, to mobile and wireless networks and now towards a converged voice and data infrastructure. This convergence is based on the spread of the Internet Protocol, where VoIP is developing. Due to IP network characteristics, hackers are able to compromise and take control of different aspects of IP telephony such as signaling informat...

The functional and cost advantages of Internet telephony are evident. By today's technical standards, however, Voice Over IP (VoIP) is still less secure than traditional telephony. At the same time, the hacker scene is constantly looking for new weak spots and developing ingenious methods of attack to gain access to confidential information and penetrate further into the network.

The presence of voice-over-IP traffic in the Internet is constantly increasing, as it offers improved connectivity and quality-of-service comparable to classical telephony at costs that the rival circuit-switched telephony systems cannot match. This paper evaluates the audio quality of voice-overIP calls that use the Datagram Congestion Control Protocol (DCCP), a congestion-controlled alternati...

IP Multimedia Subsystem (IMS) has resulted from the work of the Third Generation Partnership Project (3GPP) toward specifying an all-IP communication service infrastructure (24.229 2009). Mainly looking at the needs and requirements of mobile operators, the 3GPP first specified IMS as a service architecture combining the Internet’s IP technology and wireless and mobility services of current mob...

ENUM creates many new market opportunities and raises several important policy issues related to the implementation and administration of the ENUM database and services. ITU’s recent World Telecommunications Policy Forum 2001 dealt with the emergence of ENUM as an important numbering issue of IP telephony. This paper prepares some important emerging issues of ENUM administration and policy by t...

The corporate usage of the telephony services has been transformed by VoIP (Voice over IP), which changed the business model for that market. VoIP is a technological innovation, with high impact on the business of the suppliers of corporate telephony systems and a great potential to introduce new players to the market. This paper provides an analysis of VoIP's impact on the corporate telephony ...

This document presents a framework for supporting authorized, emergency-related communication within the context of IP telephony. We present a series of objectives that reflect a general view of how authorized emergency service, in line with the Emergency Telecommunications Service (ETS), should be realized within today’s IP architecture and service models. From these objectives, we present a c...

Session Initiation Protocol, SIP, provides controlplane signaling for the IP networks. SIP enables initiating, modifying and terminating sessions for a user, while maintaining neutrality to physical media capabilities and using other protocols to negotiate these. SIP assumes that the transport layer is inherently unreliable and as such provides transport layer mechanisms. For target device disc...

This paper presents the design and analysis of a multilayer protection scheme against denial-of-service (DoS) attacks in IP telephony enabled enterprise networks. While there are many types of DoS attacks, we focus on flood-based attacks using application layer and transport layer signaling messages in IP telephony. We design sensors to detect and control these types attacks and consider differ...

Networked multimedia applications require stringent real-time QoS guarantees. Successful deployment of such applications closely depends on the performance of the underlying data network. The characteristics and the QoS requirements of these applications are different from traditional data applications. Hence, prior to deployment it is necessary to evaluate a network from a multimedia perspecti...