Voice over IP (VoIP) is in wide use today, replacing phone lines in many scenarios. However, often, security isn’t considered well enough, even though many security attacks are already known. More research on VoIP security is needed to enhance the level of security of VoIP systems and to show the implications of failing to take appropriate security measures. This paper presents a short introduc...

VoIP over WLAN is poised to become an important Internet application. However, two major technical problems that stand in the way are 1) low VoIP capacity in WLAN; 2) unacceptable VoIP performance in the presence of coexisting traffic from other applications. With each VoIP stream typically requiring less than 10 Kbps, an 802.11b WLAN operated at 11 Mbps could in principle support more than 500...

VoIP isn’t secure since it uses the Internet to which many people connect simultaneously. In this paper, we designed and implemented a Wireless VoIP + VPN system with which secure telephone calls are possible using the open project SIP VoIP Gateway, 'Asterisk' and 'OpenVPN'. Key-Words: VoIP, VPN, SIP, Wireless, Security, WiFi

Voice over Internet Protocol (VoIP) is a way to carry out a telephonic conversation over a data network. VoIP applications, with SIP and RTP, promise converged telecommunications and data services that are cheaper, more versatile and provide good voice quality as compared to traditional offerings. Although VoIP is widely used, VoIP on mobile devices is still in its infancy. Currently, there are...

These days a massive deployment of VoIP is taking place over IP networks. VoIP deployment is a challenging task for network researchers and engineers. This paper presents a detailed simulation approach for deploying VoIP successfully. The simulation uses the OPNET network simulator. Recently OPNET has gained a considerable popularity in both academia and industry, but there is no formal or know...

Owing to the enormous growth of VoIP applications, an effective means of identifying VoIP is now essential for managing a number of network traffic issues, such as reserving bandwidth for VoIP traffic, assigning high priority for VoIP flows, or blocking VoIP calls to certain destinations. Because the protocols, port numbers, and codecs used by VoIP services are shifting toward proprietary, encr...

Voice over internet protocol (VoIP) is a method of providing phone services over dedicated public IP networks. It allows significant cost savings over traditional Public Switched Telephone Networks (PSTN). Speech quality, as perceived by the users of VoIP telephony, is critically important. Signal quality of the VoIP system is degraded by various network layer problems, which include delay, pac...

Voice over IP (VoIP) is a key driver in the evolution of voice communications, and the high transmission rate property of High Speed Packet Access (HSPA) is expected to satisfy the strict delay requirements of VoIP. Therefore, the aim of this paper is to evaluate the performance of VoIP service in HSPA network. This paper presents a mathematical model for VoIP capacity in HSPA under the constra...

In this research, we propose to implement Secure Real Time Transport Protocol (SRTP) on VoIP services in campus environment. Today, the deployment of VoIP in campus environment over wireless local area network (WLAN) is not considered on security during communication between two parties. Therefore, this study is to analyzed SRTP performance on different VoIP codec selection over wired. We have ...

In this thesis, we focus on large scale Voice over IP (VoIP) deployment over heterogeneous Internet environments. We first present an overview of VoIP coding and transmission mechanisms. Then, we investigate performance limitations in the case of a large number of VoIP flows transported over wired Internet links between peer VoIP gateways. We address, in the first part of the thesis, the need t...