In Pakistan, the VoIP service is gaining popularity. By the end of 2014, the total number of broadband subscribers exceeded 3.35 million and the total number of mobile 3G subscribers were approximately 4 million. The service providers in Pakistan continue to invest in infrastructure and supporting regulatory policies fueling the development of infrastructure. It is expected that such an environ...

Voice over Internet Protocol (VoIP) is being widely deployed to offer users low-cost alternatives for long-distance and international telephone calls. However, for users who are accustomed to the high-quality sound offered by traditional Public Switched Telephone Network (PSTN) service, VoIP voice quality often pales in comparison. Voice quality in VoIP networks widely varies as a result of sev...

Voice-over-IP (VoIP) technology has come of age and is quickly gaining momentum on Broadband networks. VoIP packetizes phone calls through the same routes used by network and Internet traffic and is consequently prone to the same cyber threats that plague data networks today. These include denial-of-service attacks, worms, viruses, and hacker exploitation. In addition to these traditional netwo...

Voice over Internet Protocol (VoIP) over Wireless Local Area Networks (WLANs) is an important application of WLANs and it has gained more and more attention recently. In this article, we analyse the maximum number of VoIP calls supportable in a WLAN and propose a new call admission control strategy, namely, Adaptive Transmission Interval Call Admission Control (ATICAC) to enhance VoIP calls in ...

The quality of speech signal over a VoIP system is degraded by various network layer problems which include jamming, jitter, packet loss. Different types of noises also degrade the quality of speech signal such as external noise and quantization noise. This paper improves the quality of VoIP speech signal affected by these noises and network layer problems. The quality of degraded VoIP speech s...

VoIP has become a major application of multimedia communications over IP. Many initiatives around the world focus on the detection of attacks against VoIP services and infrastructures. Because of the lack of a common labeled data-set similarly to what is available in TCP/IP network-based intrusion detection, their results can not be compared. VoIP providers are not able to contribute their data...

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...