As Voice over IP (VoIP) applications become increasingly popular, they are more and more facing security challenges that have not been present in the traditional Public Switched Telephone Network (PSTN). One of the reasons is that VoIP applications rely heavily on external Internet-based infrastructures (e.g., DNS server, web server), so that vulnerabilities of these external infrastructures ha...

In this paper, Cross-layer design has been used to provide quality of service (QoS) and security at the same time for VOIP over the wireless ad-hoc network. In this paper the authors extend their previous work (i.e. Multi-path Multi-Channel Protocol Design for Secure QoS-Aware VOIP in Wireless Ad-Hoc Networks) by adding transport and application layers considerations. The goal of this paper is ...

The speech of the Voice over Internet Protocol (VoIP) system is degraded by network layer problems which include delay, packet loss and jitter. The implementation of signal through digital signal processor can improve the quality of degraded VoIP signal. The work in this paper presents the comparison of speech quality for narrowband and wideband VoIP using TMS320C6713 DSP processor. The VoIP si...

IEEE 802.11 WLAN has high data rate (e.g., 11Mbps for 802.11b and 54Mbps for 802.11g) while voice stream of VoIP has low data rate requirement (e.g., 29.2Kbps). One may therefore expect WLAN to be able to support a large number of VoIP sessions (e.g., 200 and 900 sessions in 802.11b and 802.11g, respectively). Prior work by one of the authors, however, indicated that 802.11 is extremely ineffic...

Abstract The use of Voice over Internet Protocol (VoIP) innovation is rising due to its various merits. Nevertheless, the ineffective bandwidth a key dilemma that restricts fast-rising VoIP innovation. main factor behind this sizable packet preamble. This research creates technique address created known as payload elimination (PldE). fundamental concept PldE exploit information (elements) pream...

The traditional circuit-switched telecommunication network and the packet-switched data network are converging to a single packet-switched network. One important application of the converged network is telephony communications, also referred to as VoIP (Voice over IP). Call signaling protocols, such as H.323, SIP and MGCP, have been developed to support VoIP communications. To enable devices us...

Skype, Google Talk, Yahoo voice etc. are all applications that enable the use of the Internet for voice conversations. They offer cost effectiveness and are easy to use, and due to these reasons many new VoIP applications are coming into existence. However, all forms of communications need to be monitored for security purposes to ensure their correct usage. With the development of more and more...

In recent years Voice over Internet Protocol (VoIP) has become a popular multimedia application over the Internet. At the same time critical security issues in VoIP have started to emerge. The Session Initiation Protocol (SIP) is a predominant signalling protocol for VoIP. It is used to establish, maintain and terminate VoIP calls, playing a crucial role in VoIP. This paper is aimed at developi...

Recently, Voice over IP (VoIP) has become an important service for the future internet. However, for ubiquitous wireless VoIP services, greater coverage will be necessary as promised by the advent of e.g. 802.11 WLAN based wireless meshed networks. Unfortunately, the transmission of small (voice) packets imposes high overhead which leads to low capacity for VoIP over 802.11 based multihop meshe...

Voice over IP (VoIP) is a technology to transport media over IP networks such as the Internet. VoIP has the capability of connecting people over packet switched networks instead of traditional circuit switched networks. Recently, the InterAsterisk Exchange Protocol (IAX) has emerged as a new VoIP which is gaining popularity among VoIP products. IAX is known for its simplicity, NAT-friendliness,...