VoIP is a rapidly growing technology that enables the transport of voice over data networks such as the public Internet. VoIP became a viable alternative to the public switched telephone networks (PSTNs). In parallel, a dramatic increase is happening in the deployment of Wireless Local Areas Networks (WLAN) in buildings and corporate campuses. Nowadays, WLAN is mostly used for ordinary data ser...

Voice over IP (VoIP) is one of the fastest growing applications on the Internet. Concurrently, 802.11 Wireless LANs (WLANs) have become ubiquitous in residential, enterprise, campus and public networks. Currently the majority of traffic on WLANs is data traffic but as more people use wireless networks as their primary access medium, a greater portion of traffic will be real-time traffic such as...

Voice over Internet Protocol (VoIP) over Wireless Local Area Network (WLAN) is becoming popular thanks to its cost efficiency. However, it has been a challenge to provide good quality of VoIP services in WLANs, which is due mainly to (i) the nature of contention-based channel access of WLAN Medium Access Control (MAC); (ii) the presence of coexisting non-real-time data traffic; and (iii) the ti...

Open communication over the Internet poses a serious threat to countries with repressive regimes, leading them to develop and deploy networkbased censorship mechanisms within their networks. Existing censorship circumvention systems face different difficulties in providing unobservable communication with their clients; this limits their availability and poses threats to their users. To provide ...

In VoIP, proxies are used by end-devices to perform a number of tasks including call setup and routing. Setup and routing is achieved through the exchange of call control messages which are forwarded among all involved proxies as well as the communicating end-devices. This paper will explore the information exchanged in Voice-over-IP (VoIP) call control messages and any possible implications th...

The ubiquity and convergence of mobile telephony and the Internet leads many to believe that future isochronous telephony data will be transported in the form of Voice-over-IP (VoIP) datagrams. This paper investigates the modelling and aggregation of multiple VoIP streams. The relationship between the number of VoIP sources, output link rate and certain teletraffic metrics is investigated. Ther...

VoIP over wireless local area network (WLAN) is an important application of WLAN and gaining more and more attention recently. In this paper, we analyze the maximum number of VoIP calls in WLAN and propose a new call admission control strategy, namely, adaptive transmitting interval call admission control (ATICAC) to enhance VoIP calls in 802.11 WLANs. In ATICAC strategy, Base Station (BS) adap...

Voice over IP (VoIP) services have become prevalent lately because of their potential advantages such as economic efficiency and useful features. Meanwhile, Session Initiation Protocol (SIP) is being widely used as a session protocol for the VoIP services. Many mobile VoIP applications have recently been launched, and they are becoming attractive targets for attackers to steal private informati...

In this paper, an efficient scheduling scheme is proposed to increase the available capacity of VoIP services over Evolved UTRA uplink. On top of the advantages of persistent scheduling, the proposed scheme adaptively share the resources of two VoIP users to get early-termination gain of dynamic scheduler. Through system-level simulations, the performance of the proposed algorithm is evaluated ...

Internet telephony –or Voice over Internet Protocol (VOIP)– has the pote ntial to transform the world of voice communicati ons more profoundl y than anything since the inv ention of the telephon e itself. As tele communications incumbents and a range of new entrants begin rolling out commercial VOIP services, policymakers around the world are grappling with the regulatory implications. In the U...