• The Transactions of the Korea Information Processing Society
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• v.7 no.11S
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• pp.3684-3693
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• 2000

In this paper, performance of a nonblocking high speed packet switch with switching capacity m which adopts a dynamic priority control function (DPCF) of a threshold- based Bernoulli priority jump (TBPJ) scheme is considered. Each input queue has two separate buffers with different sizes for two classes of traffics, delay-sensitive and loss-sensitive traffics, and adopts a TBPJ scheme that is a general state-dependent Bernoulli scheduling scheme. Under the TBP] scheme, a head packet of the delay-sensitive traffic buffer goes into the loss -sensitive traffic buffer with Hernoulli probability p according to systems states that represent the buffer thresholds and the number of packets waiting for scheduling. Performance analysis shows that TBPJ scheme obtains large performance build-up for the delay-sensitive traffic without performance degradation for the loss-sensitive traffic. In addition to, TBP] scheme shows better performance than that of HOL scheme.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10b
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• pp.1629-1632
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• 2000

인터넷 트래픽의 폭발적인 증가로 인해 라우터에서 목적지로 포워딩 해야 할 트래픽의 양도 함께 증가하게 되었다. 그와 같은 트래픽들 중에 최근에 급격히 증가하고 있는 음성트래픽의 주를 이루는 것이 바로 인터넷 전화로 발생되는 트래픽들이다. 본 논문에서는 인터넷 전화시 발생하는 음성트래픽의 특성에 대해 살펴보고, 라우터에서 트래픽 폭주시 이를 제어하는 큐잉 방식을 비교분석하고, MNS(MPLS Network Simulation)툴을 이용하여 코어망을 MPLS 네트워크로 구성한 후 UDP 음성트래픽을 생성하여 각 라우터(LSR: Label Switch Router)의 버퍼에서 요구되어지는 폭주제어기법들에 대해 시뮬레이션을 하여 그것을 통해 얻은 결과를 바탕으로 실제 인터넷 전화 시스템의 통화품질에 적절하게 대처할 수 있는 큐잉 기법을 고찰한다.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.4
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• pp.452-456
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• 2010

In wireless sensor networks, due to the many-to-one convergence of upstream traffic, congestion more probably appears. Network congestion can be alleviated by controlling incoming traffic, but using traffic control can violate fidelity level required by applications. In this paper, we propose multipath-based congestion control scheme alleviating congestion by resource control for wireless sensor networks. When congestion occurs, the multipath-based congestion control scheme distributes network traffic through multiple alternate paths, and consequently, the scheme enables to detour in the congested spot and increase resource utilization. Our results show that our multipath-based congestion control scheme can satisfy fidelity level required by applications and alleviate congestion effectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.7C
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• pp.670-676
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• 2002

The object of ATM network is to the guarantee quality of service(QoS). Therefore, various of traffic management schemes have been proposed. Among these schemes, call admission control(CAC) is very important to provide real-time services and ON-OFF model, which is single source traffic model, has been used. But ON-OFF model differ from GCRA(Generic Cell Rate Algorithm) controlled traffic in ATM network. In this paper, we analyze the traffic, which is controlled as dual GCRA, and propose TWM(Three-state Worst-case Model), which is new single source traffic model. We also proposed CAC to guarantee peak-to-peak CDV(Cell Delay Variation) based on the TWM. In experiments, ON-OFF model and TWM are compared to show that TWM is superior to ON-Off model in terms of QoS guaranteeing.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.8
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• pp.1475-1484
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• 1994

In this paper, a priority scheduling algorithm with double threshold and a traffic control mechanism with hysteresis effect are proposed. The double threshold priority scheduling is studied based on HOL and QLT. The hysteresis effect traffic control is specified by hysteresis effect QLT and traffic rate control. According to the simulation results, it can be shown that the proposed dynamic priority scheduling brings better processing performance than the existing QLT algorithm. And the results demonstrate that QLT and traffic rate control with hysteresis effect enhance the performance in comparison with those of single threshold.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7B
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• pp.1268-1278
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• 1999

In this paper, we propose an analytic method for dimensioning of traffic descriptors at the leaky bucket-based UPC for VBR MPEG video traffic on ATM networks. We analytically derive cell violation probabilities at the UPC by using the proposed scene-based video traffic model, and then we show that it is possible to select sets of traffic descriptors that have the same required violation probability. For two example video traces, numerical results show that our proposed traffic descriptors dimensioning method can approximate well the simulation-based traffic control results of the real video traces. When the effective bandwidth allocation method of an ON/OFF model is used for the call admission control in the networks, we present an efficient traffic descriptor selection method by studying the allocated bandwidth to each possible traffic descriptor set.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.1031-1034
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• 2007

다양한 유무선 단말의 등장과 함께 원하는 곳에서 시간에 제한없이 네트워크에 접속할 수 있는 유비쿼터스 세상이 눈앞으로 다가왔다. 네트워크 접속이 현대인 생활의 일부분이 된 현실에서 과다 트래픽 발생으로 인한 급작스런 네트워크 상의 장애는 유비쿼터스 환경에서 무엇보다도 큰 위협이라 할 수 있다. 따라서 비정상적으로 발생한 과다 트래픽을 빠르게 탐지하여 대응하는 것은 유비쿼터스 환경을 안전하게 보호하기 위한 필수 요소라 할 수 있다. 본 논문에서는 기존의 트래픽 분석과는 달리 흐르는 네트워크 패킷의 5 tuple 정보를 실시간으로 수집하여 과다/이상 트래픽을 즉각적으로 탐지하고, 이를 자동으로 제어하는 메커니즘에 대해서 소개하고 있다. 실시간으로 8초마다 트래픽 정보를 수집하고 이를 분석하여 트래픽의 특성을 구분 및 위협도를 분석하여 이를 바탕으로 트래픽 제어 정책을 생성 및 적용하는 전반적인 과정에 대한 것이다. 여기에는 본 메커니즘을 실제 테스트망에서 시험한 결과도 포함하고 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.1185-1188
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• 2005

비정상 행위에 대한 true/false 방식의 공격 탐지 및 대응방법은 높은 오탐지율(false-positive)을 나타내기 때문에 이를 대체할 새로운 공격 탐지방법과 공격 대응방법이 연구되고 있다. 대표적인 연구로는 트래픽 제어 기술을 이용한 단계적 대응방법으로, 이 기술은 비정상 트래픽에 대해 단계적으로 대응함으로써 공격의 오탐지로 인하여 정상 서비스를 이용하는 트래픽이 차단되지 않도록 하는 기술이다. 비정상 트래픽 중 포트스캔 공격은 네트워크 기반 공격을 위해 공격대상 호스트의 서비스 포트를 찾아내는 공격으로 이 공격을 탐지하기 위해서는 일정 시간동안 특정 호스트의 특정 포트에 보내지는 패킷 수를 모니터링 하여 임계치와 비교하는 방식의 true/false 방식의 공격 탐지방법이 주로 사용되었다. 비정상 트래픽 제어 프레임워크(Abnormal Traffic Control Framework)는 true/false 방식의 공격 탐지방법을 이용하여 공격이 탐지되었을 때, 처음에는 트래픽 제어로 대응하고 같은 공격이 재차 탐지되었을때, 차단하여 기존의 true-false 방식의 공격 탐지 및 대응방법이 가지는 높은 오탐지율을 낮춘다. 하지만 포트스캔 공격의 특성상, 공격이 탐지된 후 바로 차단하지 못하였을 경우, 이미 공격자가 원하는 모든 정보를 유출하게 되는 문제가 있다. 본 논문에서는 기존의 True/False 방식의 포트스캔 공격 탐지방법에 퍼지 로직 개념을 추가하여 공격 탐지의 정확성을 높이고 기존의 탐지방법을 이용하였을 때보다 신속한 트래픽 제어 및 차단을 할 수 있는 방법을 제안한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1031-1041
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• 2014

In this paper, we propose a traffic load control scheme, called fast congestion control (FCC), for a satellite channel using enhanced random access schemes. The packet repetition used by enhanced random access schemes increases not only the maximum throughput but also the sensitivity to traffic load. FCC controls traffic load by using an access probability, and estimates backlogged traffic load. If the backlogged traffic load exceeds the traffic load corresponding to the maximum throughput, FCC recognizes congestion state, and processes the backlogged traffic first. The new traffic created during the congestion state accesses the channel after the end of congestion state. During the congestion state, FCC guarantees fast transmission of the backlogged traffic. Therefore, FCC is very suitable for the military traffic which has to be transmit urgently. We simulate FCC and other traffic load control schemes, and validate the superiority of FCC in latency.

• Journal of the Korea Society of Computer and Information
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• v.14 no.4
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• pp.69-76
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• 2009

The construction of Internet IP-based Network is composed of router and switch models in a variety of companies. The construction by various models causes the complexity of the management and control as different types of CLI is used by different company to filter out abnormal traffics like worm, virus, and DDoS. To improve this situation, IETF is working on enacting XML based configuration standards from NETCONF working group, but currently few commands processing at the level of operation layer on NETCONF are only standardized and it's hard for unified control operation process between different make of system as different company has different XML command to filter out abnormal traffics. This thesis proposes ways to prevent abnormal attacks and increase efficiency of network by re-routing the abnormal traffics coming thru unified control for different make of systems into Sinkhole router and designing a control system to efficiently prevent various attacks after checking the possibility of including abnormal traffics from unified control operation.