• Affects of queuing mechanisms on RTP traffic: comparative analysis of jitter, end-to-end delay and packet loss

      Epiphaniou, Gregory; Maple, Carsten; Sant, Paul; Reeve, Matthew (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2010)
      The idea of converging voice and data into a best-effort service network, such as the Internet, has rapidly developed the need to effectively define the mechanisms for achieving preferential handling of traffic. This sense of QoS assurance has increased due to the enormous growth of users accessing networks, different types of traffic competing for available bandwidth and multiple services running on the core network, defined by different protocols and vendors. VoIP traffic behaviour has become a crucial element of the intrinsic QoS mainly affected by jitter, latency and packet loss rates. This paper focuses on three different mechanisms, DropTail (FIFO), RED and DiffServ, and their effects on real-time voice traffic. Measurements of jitter, end-to-end delay and packet loss, based on simulation scenarios using the NS-2 network simulator are also presented and analyzed.
    • Anonymity networks and the fragile cyber ecosystem

      Haughey, Hamish; Epiphaniou, Gregory; al-Khateeb, Haider; University of Northumbria; University of Bedfordshire (Elsevier, 2016-03)
      It is well known that government agencies have had the capability to eavesdrop on public switched telephone networks for many decades.1 However, with the growing use of the Internet and the increasing technical capabilities of agencies to conduct mass surveillance, an individual's right to privacy is of far greater concern in recent years. The ethical issues surrounding privacy, anonymity and mass-surveillance are complicated, with compelling arguments for and against, due in part to the fact that privacy and anonymity are desired by criminals and terrorists, not just individuals who care about their privacy.
    • Effects of iterative block ciphers on quality of experience for Internet Protocol Security enabled voice over IP calls

      Safdar, Ghazanfar Ali; Sant, Paul; Epiphaniou, Gregory; Maple, Carsten (IET, 2012)
      Voice over IP (VoIP) is the technology used to transport real-time voice over a packet-switched network. This study analyses the effects of encrypted VoIP streams on perceived Quality of Experience (QoE) from a user's perspective. An in-depth analysis on how the transparent nature of encryption can influence the way users perceive the quality of a VoIP call have been investigated by using the E model. A series of experiments have been conducted using a representative sample of modern codecs currently employed for digitising voice, as well as three of the most commonly used iterative block ciphers for encryption (DES, 3DES, AES). It has been found that the Internet Protocol Security encryption of VoIP strongly relates to the payload sizes and choice of codecs and this relationship has different effects on the overall QoE as measured by the E model, in terms of the way that users perceive the quality of a VoIP call. The main result of this paper is that the default payload shipped with the codecs is not the optimal selection for an increased number of VoIP calls, when encryption is applied and a minimum level of QoE has to be maintained, per call.
    • How technology can mitigate and counteract cyber-stalking and online grooming

      al-Khateeb, Haider; Epiphaniou, Gregory; National Centre for Cyberstalking Research (Elsevier, 2016-01)
      With the virtual world becoming part of the social lives of adults and minors alike, new attack vectors emerged to increase the severity of human-related attacks to a level the community have not experience before. This article investigates and shares an outline on how technology could emerge further to counteract and mitigate the damage caused by online perpetrators. The review encourages approaching online harassment, stalking, bullying, grooming and their likes with an Incident Response methodology in mind. This includes a detection phase utilising automated methods to identify and classify such attacks, conduct digital forensic investigations to analyse the nature of the offence and reserve evidence, taking preventive measures as part of the reaction towards the problem such as filtering unwanted communications and finally looking at how we can rely on applicable computing to support and educate the victims.