ABSTRAKGSM VoIP Gateway digunakan untuk menghubungkan jaringan VoIP dengan jaringan GSM sehingga memungkinkan VoIP client melakukan komunikasi dengan VoIP client lain melalui jaringan GSM sehingga ...biaya komunikasi dapat ditekan. Pada penelitian ini, telah dirancang dan direalisasikan sistem IP PBX yang dihubungkan ke jaringan GSM menggunakan GSM VoIP Gateway. Evaluasi kinerja GSM VoIP Gateway pada sistem IP PBX dilakukan dengan mengamati nilai parameter Quality of Service (QoS). Komunikasi antara VoIP client dengan GSM VoIP Gateway dikategorikan pada kualitas layanan VoIP yang baik karena memiliki nilai rata-rata jitter ≤ 5,7 ms, packet loss ≤ 0,18% dan delay ≤ 9,41 ms. Komunikasi antara softphone SIPdroid dengan GSM VoIP Gateway memiliki nilai rata-rata jitter 22,58 ms, paket loss 48,68%, dan delay 14,54 ms, hal ini disebabkan karena komunikasi VoIP menggunakan koneksi WiFi. Selain itu perbedaan spesifikasi perangkat keras dan perangkat lunak juga turut mempengaruhi nilai parameter QoS.Kata kunci: GSM VoIP Gateway, IP PBX, VoIP ABSTRACTGSM VoIP Gateway is used to connect the VoIP network to the GSM network, allowing VoIP clients to communicate with other VoIP clients via the GSM network therefore the communication costs can be reduced. In this research, an IP PBX system connected to a GSM network using a GSM VoIP Gateway has been designed and realized. Performance evaluation of the GSM VoIP Gateway on the IP PBX system is carried out by observing the value of the Quality of Service (QoS) parameter. Communication between the VoIP client and GSM VoIP Gateway is categorized as a good quality VoIP service because it has an average value of jitter ≤ 5.7 ms, packet loss ≤ 0.18% and delay ≤ 9.41 ms. Communication between the SIPdroid softphone and the GSM VoIP Gateway has an average jitter value of 22.58 ms, a packet loss of 48.68%, and a delay of 14.54 ms, due to VoIP communication uses a WiFi connection. In addition, differences on hardware and software specifications also affect the value of QoS parameters.Keywords: GSM VoIP Gateway, IP PBX, VoIP
The quickly propelling Voice over Internet Protocol (VoIP) innovation, is picking up customer fascination in the business today. Its uses, including IP communication frameworks, includes the ...transmission of voice as information bundles which after achieving the getting side, reassembles and deciphers according to necessity. This encourages open just as private IP frameworks. The real drawback, keeping numerous organizations off from utilizing VoIP advances is related to the security of this framework. This paper examines a strategy and the following framework that get to arrange data for approved system gadgets. The entrance insights and data empower to follow gadget development all through the system. In addition, it offers to recognize unapproved gadgets making false endeavors to get to the system, presenting to be an approved access gadget.
VoIP technology deals with the real-time data communication for voice transfer in the form of digital packets through internet communication and facilitates public to make use of internet for video ...and phone calls. The voice data packets are transferred from source to the destination and vice versa. VoIP require high speed internet connection for data transfer on data network. It is necessary to arrive the data packet from its source to the destination with high level of reliability. It is very important to analyse link failure, packet loss, delay and jitter during the data communication. Components involved in data communication should be reliable. This paper provides a survey for step wise development and use of reliability techniques for gaining high quality of voice in VoIP network.
Voiceover Internet Protocol (VoIP) application is a vital technology that is quickly growing in the Mobile Ad hoc NETwork (MANET). Packet loss is a factor that can significantly affect the Quality of ...Service (QoS) for VoIP performance. Due to the dynamic nature of MANET, it is a challenging task to maintain the desired packet loss rate. This paper aims to enhance the performance of VoIP in the MANET using a fuzzy logic model. The input for the model is VoIP packet loss and the outputs are the optimal parameters of MANET (node number, pause time, maximum speed, and maximum connection).Network Simulator (NS2) was used to perform all simulations. MATLAB was used to implement the proposed fuzzy model. Moreover, the performance of the model was evaluated using NS2, and the results show that our proposed fuzzy model offers a significant enhancement in terms of the VoIP packet loss rate (P.LR).
Voice over Internet Protocol (VoIP) has become increasingly popular among individuals and business organisations, with millions of users communicating using VoIP applications (apps) on their smart ...mobile devices. Since Android is one of the most popular mobile platforms, this research focuses on Android devices. In this paper we survey the research that examines the security and privacy of mVoIP published in English from January 2009 to January 2014. We also examine the ten most popular free mVoIP apps for Android devices, and analyse the communications to determine whether the voice and text communications using these mVoIP apps are encrypted. The results indicate that most of the apps encrypt text communications, but voice communications may not have been encrypted in Fring, ICQ, Tango, Viber, Vonage, WeChat and Yahoo. The findings described in this paper contribute to an in-depth understanding of the potential privacy risks inherent in the communications using these apps, a previously understudied app category. Six potential research topics are also outlined.
Mobile telecommunications are converging towards all-IP solutions. This is the case of the Long Term Evolution (LTE) technology that, having no circuit-switched bearer to support voice traffic, needs ...a dedicated VoIP infrastructure, which often relies on the IP Multimedia Subsystem architecture. Most telecom operators implement LTE-A, an advanced version of LTE often marketed as <inline-formula> <tex-math notation="LaTeX">4{G} + </tex-math></inline-formula>, which achieves data rate peaks of 300 Mbps. Yet, although such novel technology boosts the access to advanced multimedia contents and services, telco operators continue to consider the VoIP market as the major revenue for their business. In this work, the authors propose a detailed performance assessment of VoIP traffic by carrying out experimental trials across a real LTE-A environment. The experimental campaign consists of two stages. First, we characterize VoIP calls between fixed and mobile terminals, based on a data-set that includes more than 750,000 data-voice packets. We analyze quality-of-service metrics such as round-trip time (RTT) and jitter, to capture the influence of uncontrolled factors that typically appear in real-world settings. In the second stage, we further consider VoIP flows across a range of codecs, looking at the trade-offs between quality and bandwidth consumption. Moreover, we propose a statistical characterization of jitter and RTT (representing the most critical parameters), identifying the optimal approximating distribution, namely the Generalized Extreme Value (GEV). The estimation of parameters through the Maximum Likelihood criterion, leads us to reveal both the short- and long-tail behaviour for jitter and RTT, respectively.
We present a comprehensive survey of Voice over IP security academic research, using a set of 245 publications forming a closed cross-citation set. We classify these papers according to an extended ...version of the VoIP Security Alliance (VoIPSA) Threat Taxonomy. Our goal is to provide a roadmap for researchers seeking to understand existing capabilities and to identify gaps in addressing the numerous threats and vulnerabilities present in VoIP systems. We discuss the implications of our findings with respect to vulnerabilities reported in a variety of VoIP products. We identify two specific problem areas (denial of service, and service abuse) as requiring significant more attention from the research community. We also find that the overwhelming majority of the surveyed work takes a black box view of VoIP systems that avoids examining their internal structure and implementation. Such an approach may miss the mark in terms of addressing the main sources of vulnerabilities, i.e., implementation bugs and misconfigurations. Finally, we argue for further work on understanding cross-protocol and cross-mechanism vulnerabilities (emergent properties), which are the byproduct of a highly complex system-of-systems and an indication of the issues in future large-scale systems.
Voice over Internet Protocol (VoIP) an emerging new technologies is based on realtime communication of data by sending and receiving digital signals using Internet Protocols (IP). VoIP has become ...popular in business organization and scientific communities. Voice coder (Codec) named as coder and decoder, play an important role in packet switch network for transfer of audio and video data. A signalling protocol known as Session Initiation Protocol (SIP) is used for data communication between nodes in VoIP network. In this paper we survey on security related issues in VoIP communication system and covered several security attacks. We proceed with survey on all the problems that have big effects on VoIP security and challenges such as data manipulation, substitution attack, power backups, jitter, latency and delay. Finally, we conclude the paper with further research on security of VoIP communication system.
VoIP (Voice over Internet Protocol) is one of the most prevalent services for the mobile users. An enormous amount of audio and video data is transmitted over VoIP communication continuously, to make ...it potentially available for stealth message transfer. The existing covert channel schemes focus on modifying packet payload or inter-packet delays, the former kind is easy to be detected since a minor modification may lead to distinct abnormalities, while the latter is too sensitive to network jitter due to its short inter-packet delays. Hence, to effectively construct covert channel becomes a challenge, and requires investigation in using mobile VoIP traffic for robust and stealthy covert communication. In this paper, we propose a covert channel scheme which communicates by rearranging the packet sending sequences while keeps the undetectability and robustness. Unlike the existed packet rearranging covert channels which may concentrate on packet rearranging according to the existed packet features such as packet id and packet length, the proposed scheme focuses on building packet rearranging covert channel whose function is regardless of the variation on legitimate traffic. According to the hash value of the payload, the packets are classified into delimiter packets and carrier packets, and the covert message is embedded onto a number of carrier packets (NoCP) between the relative delimiter packets. Moreover, to mitigate the interference from channel noise, the differences between two correlative NoCPs are utilized as the codewords by redundantly partitioning their values into 1-bit symbols. The channel parameters are adjustable to trade off between the efficiency and security. The corresponding experiments are conducted over three kinds of typical mobile VoIP traffics to evaluate the undetectability, robustness and throughput of our scheme. Results of the BER (bit error rate) and KS (Kolmogorov-Smirnov) test show that the scheme is robust and stealthy.
We present a survey of authentication and key agreement schemes that are proposed for the SIP protocol. SIP has become the center piece for most VoIP architectures. Performance and security of the ...authentication and key agreement schemes are two critical factors that affect the VoIP applications with large number of users. Therefore, we have identified, categorized and evaluated various SIP authentication and key agreement protocols according to their performance and security features. Although the performance is inversely proportional to the security features provided in general, we observed that there are successful schemes from both the performance and security viewpoint.
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