• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.5
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• pp.942-949
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• 2006

The VoIP(Voice over IP) has been worldwide used and already put to practical use in many fields. However, it is needed to ensure secret of VoIP call in a special situation. It is relatively difficult to eavesdrop the commonly used PSTN in that it is connected with 1:1 circuit. However, it is difficult to ensure the secret of call on Internet because many users can connect to the Internet at the same time. Therefore, this paper suggests a new model of Internet telephone for eavesdrop prevention enabling VoIP(using SIP protocol) to use the VPN protocol and establish the probability of practical use comparing it with Internet telephone.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.12
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• pp.18-26
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• 2003

In this paper, we design and implement a QoS control function in the SIP-based VoIP system. As a network infrastructure for VoIP service, we select the Intserv over Diffserv architecture where the network resources are managed by a call admission control mechanism. The SIP protocol extended to support QoS signaling procedure is modulized to operate independently with the infrastructure. The performance of the QoS-enabled VoIP system is verified by experiments.

• Venture DIGEST
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• s.103
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• pp.8-11
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• 2007

인터넷전화(VoIP)는 "Voice over Internet Protocol"의 약자로 기존의 회선교환망(Circuit Network)이 아닌 인터넷망(IP Network)을 통해 패킷단위로 전송하여 통화권 구분없이 음성등을 송신하거나 수신하는 새로운 방식의 전화서비스이다.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.11-14
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• 2005

In this paper, we propose a method for transmitting SMS(Short Message Service) for VoIP(Voice over IP) service supporting multi-protocol. The multi-protocol VoIP under consideration are generally composed of H.323, SIP and MGCP and Most ITSPs(Internet Telephony Service Provider) provide VoIP service with H.323 and SIP now. SMS is killer application in mobile telecom service and many people of various field use that service. For example, user can send many SMS messages and substitute e-mail. Also SMS can be provided with various internet application. Ahn, legacy phone of KT, can use SMS. Therefore VoIP phone also can be required with the same requirement. With the multi-protocol VoIP we will propose several methods sending efficiently SMS. To show the validity of the proposed method some examples are given in which the results can be expected by intuitive observation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.245-248
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• 2011

Voice over Internet protocol(VoIP) is call's contents using the existing internet. Thus, in common with the Internet service has the same vulnerability. In addition, unlike traditional PSTN remotely without physical access to hack through the eavesdropping is possible. Cyber terrorism by anti-state groups take place when the agency's computer network and telephone system at the same time work is likely to get upset. In this paper is penetration testing for security threats(Call interception, eavesdropping, misuse of services) set out in the NIS in the VoIP. In addition, scenario writing and penetration testing, hacking through the Voice over Internet protocol at the examination center will study discovered vulnerabilities. Vulnerability discovered in Voice over Internet protocol presents an attack and defense plan.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1391-1394
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• 2005

The VoIP (Voice over IP) is being used world-widely and already put to practical use in many fields. However, it is needed to ensure the security of VoIP call in special situations. It is relatively difficult to eavesdrop commonly used PSTN network in that a 1:1 circuit connects it. However, it is difficult to ensure the security of a call on Internet because many users are connected to the Internet concurrently. This paper suggests a new model for Internet telephony to prevent eavesdrops, using VoIP (using SIP protocol) with the use the VPN protocol and establish the feasibility of its practical use comparing it with the conventional Internet telephony.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.990-994
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• 2003

This paper describes the VoIP(Voice over Internet Protocol) SoC(System on Chip) Design and the test board development for the function verification to support voice communication services using Internet. To implement the simple system of configuration, we designed the VoIP SoC which have ARM922T of 32bit microprocessor, IP network interface, voice signal interface, various user interface function. Also we developed test program and communication protocol to verify the function of this chip. We used several tools of design and simulation, developed and tested a test board with Excalibur which includes ARM922T microprocessor and FPGA.

• Journal of Communications and Networks
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• v.14 no.5
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• pp.510-517
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• 2012

This paper analyzes the performance of voice-over-Internet protocol (VoIP) services in terms of the system throughput, the packet delay, and the signaling overhead in a mobile WiMAX system with a hybrid automatic repeat request (HARQ) mechanism. Furthermore, a queueing analytical model is developed with due consideration of adaptive modulation and coding, the signaling overhead, and the retransmissions of erroneous packets. The arrival process is modeled as the sum of the arrival rate at the initial transmission queue and the retransmission queue, respectively. The service rate is calculated by taking the HARQ retransmissions into consideration. This paper also evaluates the performance of VoIP services in a mobile WiMAX system with and without persistent allocation; persistent allocation is a technique used to reduce the signaling overhead for connections with a periodic traffic pattern and a relatively fixed payload. As shown in the simulation results, the HARQ mechanism increases the system throughput as well as the signaling overhead and the packet delay.

• TTA Journal
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• s.71
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• pp.93-104
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• 2000

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.12
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• pp.3366-3383
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• 2012

Reliance on the Internet has introduced Voice over Internet Protocol (VoIP) to various security threats. A reliable security protocol and an authentication scheme are thus required to prevent the aforementioned threats. However, an authentication scheme often demands additional cost and effort. Accordingly, a security framework for known participants in VoIP communication is proposed in this paper. The framework is known as Randomness-Optimized Self-Securing (ROSS), which performs authentication automatically throughout the session by optimizing the uniqueness and randomness of the communication itself. Elliptic Curve Diffie-Hellman (ECDH) key exchange and Salsa20 stream cipher are utilized in the framework correspondingly to secure the key agreement and the communication with low computational cost. Human intelligence supports ROSS authentication process to ensure participant authenticity and communication regularity. The results show that with marginal overhead, the proposed framework is able to secure VoIP communication by performing reliable authentication.