• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권8호
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• pp.3701-3727
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• 2016

Recently Service Function Chaining (SFC) is promising to innovate the network service mode in modern networks. However, a feasible implementation of SFC is still difficult due to the need to achieve functional equivalence with traditional modes without sacrificing performance or increasing network complexity. In this paper, we present a configurable network service chaining (CNSC) mechanism to provide services for network traffics in a flexible and optimal way. Firstly, we formulate the problem of network service chaining and design an effective service chain construction framework based on integrating software-defined networking (SDN) with network functions virtualization (NFV). Then, we model the service path computation problem as an integer liner optimization problem and propose an algorithm named SPCM to cooperatively combine service function instances with a network utility maximum policy. In the procedure of SPCM, we achieve the service node mapping by defining a service capacity matrix for substrate nodes, and work out the optimal link mapping policies with segment routing. Finally, the simulation results indicate that the average request acceptance ratio and resources utilization ratio can reach above 85% and 75% by our SPCM algorithm, respectively. Upon the prototype system, it is demonstrated that CNSC outperforms other approaches and can provide flexible and scalable network services.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권6호
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• pp.2534-2553
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• 2018

Source routing is the routing scheme that arranges the whole path from source to target at the origin node that may suit the requirements from the upper layer applications' perspective. The centralized control in SDN (Software-Defined Networking) networks enables the awareness of the global topology at the controller. Therefore, augmented source routing schemes can be designed to achieve various purposes. This paper proposes a source routing scheme that conducts the top-K QoS-aware paths discovery in SDN. First, the novel non-invasive QoS over LLDP scheme is designed to collect QoS information based on LLDP in a piggyback fashion. Then, variations of the KSP (K Shortest Paths) algorithm are derived to find the unconstrained/constrained top-K ranked paths with regard to individual/overall path costs, reflecting the Quality of Service. The experiment results show that the proposed scheme can efficiently collect the QoS information and find the top-K paths. Also, the performance of our scheme is applicable in QoS-sensitive application scenarios compared with previous works.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권6호
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• pp.2735-2751
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• 2020

The emergence of Software Defined Networking (SDN) overcomes the limitations of traditional networking architectures. There are some advantages in SDN which are centralized global network view, programmability, and separation of the data plane and control plane. Due to the limitation of data plane storage capacity in SDN, it is necessary to process the redundancy rules of switch. In this paper, we propose a method for active detection and processing of redundant rules. We use the result generated by the customized probe package to detect redundant rules. And by checking the forwarding behavior of probe packets in the data plane, the redundancy rules are further processed. Furthermore, in order to quickly check the dynamic networks, we propose an incremental algorithms for rapidly evolve the network strategies. We conduct simulation experiments on Matlab to verify the feasibility of the algorithm. The influence of some parameters on the result are discussed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권8호
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• pp.3946-3965
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• 2018

Network anomaly detection in Software Defined Networking, especially the detection of DDoS attack, has been given great attention in recent years. It is convenient to build the Traffic Matrix from a global view in SDN. However, the monitoring and management of high-volume feature-rich traffic in large networks brings significant challenges. In this paper, we propose a moving window Principal Components Analysis based anomaly detection and mitigation approach to map data onto a low-dimensional subspace and keep monitoring the network state in real-time. Once the anomaly is detected, the controller will install the defense flow table rules onto the corresponding data plane switches to mitigate the attack. Furthermore, we evaluate our approach with experiments. The Receiver Operating Characteristic curves show that our approach performs well in both detection probability and false alarm probability compared with the entropy-based approach. In addition, the mitigation effect is impressive that our approach can prevent most of the attacking traffic. At last, we evaluate the overhead of the system, including the detection delay and utilization of CPU, which is not excessive. Our anomaly detection approach is lightweight and effective.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2016년도 춘계학술발표대회
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• pp.124-126
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• 2016

Successful deployment of the Software Defined Network (SDN) depends on its ability to cope up with network failures. There are various types of failures that may occur in an SDN. The most common are switch and link failures. It is necessary to recover the network from failures for a continuous service availability. But for the real-time services fast recovery from the failure is required to minimize the service disruption time. In the proposed work, we focused on minimizing the recovery time after the failure is detected. Once the failure is detected, the controller involvement is needed to dynamically reroute the failure disrupted flows from the failed component to an alternate path. The aim of the proposed scheme is to provide a traffic management scheme which can react to the dynamic network events by rapidly modifying the forwarding behavior of the switches for faster in-band network adaptability. The proposed scheme (1) Considers the shared data and control path delay (2) Optimally utilize the network resources (3) Eliminates the need of constant monitoring overhead at the controller which results into faster detouring and ultimately rapid recovery.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 추계학술대회
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• pp.969-972
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• 2009

유비쿼터스 사회가 도래하면서 개인의 휴대단말기가 기하급수적으로 증가하고 있다. 이러한 지능형 개인 휴대단말기는 상호간 네트워킹을 통한 정보교류를 위하여 무선 주파수를 사용하게 되고, 허가된 주파수 대역은 한정되어 있어, 전세계적으로 주파수 부족에 대한 우려감을 낳게 되었다. 이에 따라 정보통신을 위한 고성능 집적회로의 개발과 다양한 통신 프로토콜의 발전으로 새로운 종류의 소프트웨어로 정의된 무선통신방식 (SDR; Software Defined Radio)인 Cognitive Radio (CR; 인지 무선통신)이 대두하게 되었다. 이 새로운 개념의 CR은 주변의 정보를 수집하여 학습하면서 주변의 스펙트럼을 센싱하여 비어있는 채널 정보를 활용하여 통신을 수행하는 기술이다. 본 고에서는 CR 연구에 대한 세계적인 동향과 현재 이슈가 되고 있는 문제점에 대하여 분석하고 기술한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권8호
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• pp.3474-3497
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• 2016

Network Function Virtualization (NFV) and Software Defined Networking (SDN) are recently considered as very promising drivers of the evolution of existing middlebox services, which play intrinsic and fundamental roles in today's networks. To address the virtual service deployment issues that caused by introducing NFV or SDN to networks, this paper proposes an optimal solution by combining quantum genetic algorithm with cooperative game theory. Specifically, we first state the concrete content of the service deployment problem and describe the system framework based on the architecture of SDN. Second, for the service location placement sub-problem, an integer linear programming model is built, which aims at minimizing the network transport delay by selecting suitable service locations, and then a heuristic solution is designed based on the improved quantum genetic algorithm. Third, for the service amount placement sub-problem, we apply the rigorous cooperative game-theoretic approach to build the mathematical model, and implement a distributed algorithm corresponding to Nash bargaining solution. Finally, experimental results show that our proposed method can calculate automatically the optimized placement locations, which reduces 30% of the average traffic delay compared to that of the random placement scheme. Meanwhile, the service amount placement approach can achieve the performance that the average metric values of satisfaction degree and fairness index reach above 90%. And evaluation results demonstrate that our proposed mechanism has a comprehensive advantage for network application.

• 한국항행학회논문지
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• 제18권6호
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• pp.594-599
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• 2014

현재 스마트폰과 같은 무선 환경 기기의 일상화는 IEEE802.11 그룹의 무선 네트워크 사용 환경을 한층 더 확장시키고 있으며, Wi-Fi와 같은 사용자 중심의 상용화 무선 네트워크 요구가 급증하면서 이의 효과적인 활용과 사용자 중심의 끊김없는 핸드오버는 가장 중요한 논점 중에 하나이다. 그리고 현재 이슈화되고 있는 SDN은 데이터센터 내에서 OpenFlow 스위치 간의 비용 및 복잡도를 줄이는 각 플로우 라우팅을 제공한다. 이는 관리자에게 직관적인 제어를 제공하면서 사용자에게는 지연시간을 줄여주는 이점을 제공하고 있다. 본 논문에서는 SDN이 지원하는 네트워크 서비스 재구성 능력을 밀집된 무선네트워크 환경에 적용하여 끊김없는 핸드오버 매커니즘을 연구하고 성능을 검증한다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2016년도 추계학술발표대회
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• pp.119-122
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• 2016

대표적인 네트워크 기반의 이동성 기법인 PMIPv6(Proxy Mobility IPv6)은 이동 단말에 대한 끊김 없는 서비스 지원이 가능하다. 하지만 PMIPv6 기법은 단말과 홈 에이전트 간 IP Tunnel을 생성해야 하며, 그에 따른 시그널링 비용이 발생하게 된다. 또한, 단말 이동에 따른 연속적인 서비스 지원만 고려할 뿐 이동 중 발생하는 패킷 손실은 고려하지 않는 문제점이 있다. 본 논문은 이러한 문제점을 해결하기 위해 SDN(Software Defined Networks)을 적용하였다. 데이터 플레인에서 Anchor 스위치를 선정하여 이동 전 위치의 단말로 전송되던 패킷을 이동한 위치의 단말로 Re-direction 함으로써 패킷 손실을 줄이기 위한 기법을 제안한다.

• 전자통신동향분석
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• 제38권4호
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• pp.81-94
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• 2023

The increased adoption of open source security management in supply chains is gaining worldwide attention. In particular, as security and threatening situations, such as solar winds, Kaseya ransomware, and Log4j vulnerability, are becoming more common in supply chains using software (SW)-defined networks, SW bills of materials (SBOMs) for SW products should be prepared to protect major countries like the United States. An SBOM provides SW component information and is expected to become required for SW supply chain management. We focus on SW supply chain management policies and SBOM trends in major countries and private organizations worldwide for safe SW use and determine the current status of Korea and ETRI's open source SW supply chain management trends.