Phone features, e.g., 911 call, voicemail, and Do Not Disturb, are critical and necessary for all deployed VoIP systems. In this paper, we empirically investigate the security of these phone features. We have implemented a number of attacks and experimented with VoIP services by leading VoIP service providers Vonage, AT&T and Gizmo. Our experimental results demonstrate that a man-in-the-middle ...

The voice signal in Voice over Internet protocol (VoIP) system is processed through the best effort policy based IP network, which leads to the network degradations including delay, packet loss jitter. The work in this paper presents the implementation of finite impulse response (FIR) filter for voice quality improvement in the VoIP system through distributed arithmetic (DA) algorithm. The VoIP...

Phone features, e.g., 911 call, voicemail, and Do Not Disturb, are critical and necessary for all deployed VoIP systems. In this paper, we empirically investigate the security of these phone features. We have implemented a number of attacks and experimented with VoIP services by leading VoIP service providers Vonage, AT&T and Gizmo. Our experimental results demonstrate that a man-in-the-middle ...

The issues faced by law enforcement authorities concerning VoIP are very different from that of traditional telephony. VoIP provides strong encryption and a decentralised data­based network. Wiretapping is not applicable to VoIP calls and packet capturing is negated by encryption. New methods are required to collect evidence from systems running VoIP software. This paper ...

This report contains an experimental evaluation of the impact that congestion control algorithms NewReno, HTCP and CUBIC have on the latency of VoIP traffic. It was found that when a TCP flow and VoIP flow share a bottleneck link the induced delay in the VoIP flow is related to the growth of the congestion window. CUBIC induced the highest average latency in the VoIP flow and HTCP the least.

Voice over LTE (VoLTE) emerges as the basis for voice services in future cellular networks. At the same time, Quality of user Experience (QoE) assessment methods have notably evolved in the last years, especially for Voice over IP (VoIP) services. The question that rises is, are these models ready to be used for VoLTE? In this paper, we contribute to answer this question by: (i) providing a hig...

Voice over Internet protocol (VoIP) is a new way of communicating. It is a technology that allows users to make telephone calls over an IP network. This paper will describe Voice over Internet Protocol (VoIP) to a level that allows discussion of security issues and concerns. Business concerns of implementing VoIP, components of a VoIP system, and relevant security issues and concerns as they ap...

It has been increasingly popular to build voice-over-IP (VoIP) applications based on peer-to-peer (P2P) networks in the Internet. However, many such VoIP applications free-ride the network bandwidth of Internet Service Providers (ISPs). Thus their success may come at a cost to ISPs, especially those on the edge of the Internet. In this paper, we study the VoIP quality of Skype, a popular P2P-ba...

Voice-over-IP (VoIP) is one of the main applications or services, which dramatically increased the spread and usage of the Internet. VoIP describes the transmission and reception of voice and video data over networks that use the “internet protocol” (IP) as transport protocol. With the use of VoIP within company networks (intranet) investors hope to reduce the expenses for infrastructure and ma...