• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1998.10a
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• pp.144-147
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• 1998

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1998.10a
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• pp.879-882
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• 1998

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1998.10a
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• pp.131-135
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• 1998

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.11B
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• pp.1038-1049
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• 2003

Exactly measuring traffic load is the basis for efficient traffic engineering. However, precise traffic measurement involves inspecting every packet traversing a lint resulting in significant overhead on routers with high-speed links. Sampling techniques are proposed as an alternative way to reduce the measurement overhead. But, since sampling inevitably accompany with error, there should be a way to control, or at least limit, the error for traffic engineering applications to work correctly. In this paper, we address the problem of bounding sampling error within a pre-specified tolerance level. We derive a relationship between the number of samples, the accuracy of estimation and the squared coefficient of variation of packet size distribution. Based on this relationship, we propose an adaptive random sampling technique that determines the minimum sampling probability adaptively according to traffic dynamics. Using real network traffic traces, we show that the proposed adaptive random sampling technique indeed produces the desired accuracy, while also yielding significant reduction in the amount of traffic samples.

• The Journal of the Korea Contents Association
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• v.5 no.5
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• pp.172-181
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• 2005

The latest attack type against network traffic appeared by worm and bot that are advanced in DDoS. It is difficult to detect them because they are diversified, intelligent, concealed and automated. The exisiting traffic analysis method using SNMP has a vulnerable problem; it considers normal P2P and other application program to be harmful traffic. It also has limitation that does not analyze advanced programs such as worm and bot to harmful traffic. Therefore, we analyzed harmful traffic out Protocol and Port analysis. We also classified traffic by protocol, well-known port, P2P port, existing attack port, and specification port, apply singularity weight to detect, and analyze attack availability. As a result of simulation, it is proved that it can effectively detect P2P application, worm, bot, and DDoS attack.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.10B
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• pp.928-938
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• 2008

Though services requiring Quality-of-Service (QoS) guarantees such as Voice over Internet Protocol (VoIP) have been widely deployed on the internet, most of internet backbone networks, unfortunately, do not distinguish them from the best-effort services. Thus estimating the effective capacity meaning the traffic volume that the backbone networks maximally accommodate with keeping QoS guarantees for the services is very important for Internet Service Providers. This paper proposes a test-bed based on ns-2 to evaluate the effective capacity of backbone networks and then estimates the effective capacity of an experimental backbone network using the test-bed in terms of the service standard of the VoIP service. The result showed that the effective capacity of the network is estimated as between 12% and 55% of its physical capacity, which is depending on the maximum delay guarantee probability, and strongly affected by not only the type of offered workload but also the quality standard. Especially, it demonstrated that in order to improve the effective capacity the maximum end-to-end delay requirement of the VoIP service needs to be loosened in terms of the probability to guarantee.

• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.191-200
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• 2005

The brilliant achievements in computers and the internet technology make it easy for users to get useful information. But at the same time, the damages caused by intrusions and denial of service attacks are getting more worse. Specially because denial of service attacks by internet worm incapacitate computers and networks, we should draw up a disposal plan against it. So far many rule-based intrusion detection systems have been developed, but these have the limits of these ability to detect new internet worms. In this paper, we propose a system to detect intrusion and generate detection rule against scan-based internet worm, paying attention to the fact that internet worms scan network to infect hosts. The system detects internet worms using detection rule. And if it detects traffic causing by a new scan-based internet worm, it generates new detection nile using traffic information that is gathered. Therefore it can response to new internet worms early. Because the system gathers packet payload, when it is being necessary only, it can reduce system's overhead and disk space that is required.

• Electronics and Telecommunications Trends
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• v.28 no.5
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• pp.221-231
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• 2013

인터넷 접속료 정산방식은 그동안 피어링과 트랜짓 모델이 주로 활용되어 왔으나 인터넷 트래픽의 폭발적 증가, OTT 서비스 확산 등으로 망 이용대가의 적정 분담을 위해 발신자지불방식(SPNP: Send Party network Pay) 등 새로운 정산모델 도입이 필요하다는 주장도 제기되고 있다. 본고에서는 인터넷 접속료 정산방식으로 활용되어 온 피어링과 트랜짓 정산모델의 특징과 도입배경, 다양한 피어링/트랜짓 변형 모델을 살펴보고, 최근 유렵 통신사업자 협회가 제안한 발신자지불방식 정산모델의 제안 배경 및 ITU, OECD 등 국제기구에서의 논의 동향을 검토해보고자 한다.

• Information and Communications Magazine
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• v.29 no.9
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• pp.63-69
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• 2012

최근 인터넷을 통한 동영상 서비스 비중이 크게 증가하고 스마트폰과 같은 이동 단말의 빠른 보급으로 인해, 인터넷 트래픽이 폭발적으로 증가하고 인터넷 접속 환경 역시 이동 중심으로 변화하고 있다. 현재의 인터넷은 이러한 변화 추세를 수용하기 위해 근본적인 문제가 제기 되고 있어, 새로운 혁신적 접근 방식의 콘텐츠 중심 네트워크 기술이 주목 받고 있다. 본고에서는 콘텐츠 중심 네트워크의 효율적인 데이터 전송 기법을 소개하고, 특히 이동성에 관한 이슈 및 연구 동향에 대해 살펴본다.

• Information and Communications Magazine
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• v.29 no.3
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• pp.41-48
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• 2012

최근 스마트폰의 도입과 더불어서 이동 인터넷 트래픽이 급증하고 있어서 미래 인터넷의 새로운 구조를 분석 및 연구할 때 이동성(Mobility)을 중요한 설계 요구사항으로 정하고 있다. 본 고에서는 미래 인터넷에서 이동 네트워크 구조 연구의 필요성에 대해 설명한다. 또한, 이동성 관리 연구에 있어서 최근에 많은 이슈가 되고 있는 분산/동적 이동성 관리에 대해 살펴보고 국내외의 여러 연구 그룹에서 제안하고 있는 대표적인 이동 네트워크 구조 및 연구 동향에 대해 기술한다.