Voice over the Internet protocol (VoIP) is being rapidly deployed, and the convergence of the voice and data worlds is introducing exciting opportunities. Lower cost and greater flexibility are the key factors luring enterprises to transition to VoIP. Some security problems may surface with the widespread deployment of VoIP. In this article, we discuss these security problems and propose a high...

Voice/Video over IP (VoIP) systems to date have been either highly centralized or dependent on the IP multicast in nature. Global Multimedia Collaboration System is a scalable, integrated and service-oriented VoIP conferencing system, based on the XGSP collaboration framework and NaradaBrokering messaging middleware. This system can provide media and session services to heterogeneous endpoints ...

Voice over Internet Protocol (VoIP) is one of the most important technologies in the world of communication. Around 20 years of research on VoIP, some Quality of Service (QoS) problems of VoIP are still remaining. The newly emerging wireless mesh network has fundamental difficulties in supporting VoIP applications due to the MAC overheads introduced by huge amounts of small packets. Packet aggr...

Over the last years Voice-over-IP (VoIP) is getting widespread adoption from business and residential customers.The preference towards VoIP services stems from the fact that VoIP provides many ways to communicate, with a lower cost than traditional telephony. However, VoIP in its present form may allow malicious users to exploit a number of vulnerabilities, make bulk unsolicited telephony calls...

The integration of Mobile IP standard and VoIP functions makes the Mobile Voice over IP (Mobile VoIP) service feasible. In Mobile VoIP applications, the mobile users can dynamically move around different networks, and thus result in handoffs. Handoffs will introduce packets loss, and thus significantly drop the quality of service (QoS). To support the QoS, we propose in this paper a two-buffer ...

Voice over IP (VOIP) the transmis­ sion of voice over traditional packetswitched IP networks is one of the hottest trends in telecommunications. As with any new technology, VOIP introduces both opportunities and security challenges. Lower cost and greater flexibility are among the prom­ ises of VOIP for the enterprise, but security administrators will face signif­ icant issues. Administrators m...

Users of Voice over IP (VoIP) applications are sensitive to the quality of an ongoing call. We hypothesize that the quality of a VoIP session can be estimated from the first few seconds of the session and this can be generalized to other VoIP calls. Our approach is an in-band probing mechanism and does not require any external monitoring schemes or network support. We show by post processing Vo...

With the appearance of new Internet services like Voice over IP and IP television, malwares are in the way to update and extend their targets. In this paper, we discuss the emergence of a new generation of malwares attacking VoIP infrastructures and services. Such malwares constitute a real threat to the currently deployed VoIP architectures without strong security measures in place. We present...

-------------------------------------------------------------------ABSTRACT---------------------------------------------------Voice over Internet Protocol (VoIP) is a methodology and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. VoIP provides a protected transmission of private voice data betwee...

Deploying IP telephony or voice over IP (VoIP) is a major and challenging task. This paper describes an analytical design and planning simulator to assess the readiness of existing IP networks for the deployment of VoIP. The analytical simulator utilizes techniques used for network flows and queueing network analysis to compute two key performance bounds for VoIP: delay and bandwidth. The simul...