• 정보와 통신
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• 제32권7호
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• pp.82-92
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• 2015

소프트웨어 정의 네트워킹 (Software-Defined Networking: SDN)과 네트워크 기능 가상화 (Network Function Virtualization: NFV) 기술은 네트워크 산업 전반에 걸쳐 가장 중요한 기술/트렌드로 인식되고 있다. 현재 국내외 주요 기업들이 앞다투어 기술 개발을 추진하고 있으며 이를 실제 상용망에 적용하고자 하는 움직임도 활발히 진행되고 있다. 본 고에서는 유사하면서도 다른 SDN과 NFV의 개념을 명확히 살펴보고자 한다. SDN과 NFV의 역사, 핵심 기술, 활용 분야, 그리고 향후 연구 이슈를 폭넓게 제시한다.

• 정보와 통신
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• 제30권2호
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• pp.36-42
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• 2013

본 고에서는 최근 활발히 연구되고 있는 SDN (Software-Defined Networking) 기술과 관련하여 다양한 SDN의 정의와 개념을 포괄하는 표준 참조 구조 (Reference Architecture)를 제안하고, 이를 기반으로 대표적인 표준화 대상인 개방형 인터페이스, SDN 스위치 추상화와 컨트롤러 응용 언어 기술에 대해 논의한다.

• 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.

• 한국멀티미디어학회논문지
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• 제18권1호
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• pp.35-41
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• 2015

SDN(Software Defined Networking) has been considered as a new future computer network architecture and DDoS(Distributed Denial of Service) is the biggest threat in the network security. In SDN architecture, we present the technique to defend the DDoS SYN Flooding attack that is one of the DDoS attack method. First, we monitor the Backlog queue in order to reduce the unnecessary monitoring resources. If the Backlog queue of the certain server is occupied over 70%, the sFlow performs packet sampling with the server address as the destination address. To distinguish between the attacker and the normal user, we use the source address. We decide the SYN packet threshold using the remaining Backlog queue that possible to allow the number of connections. If certain sources address send the SYN packet over the threshold, we judge that this address is attacker. The controller will modify the flow table entry to block attack traffics. By using this method, we reduce the resource consumption about the unnecessary monitoring and the protection range is expanded to all switches. The result achieved from our experiment show that we can prevent the SYN Flooding attack before the Backlog queue is fully occupied.

• KNOM Review
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• 제21권2호
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• pp.35-45
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• 2018

네트워크 슬라이싱 기능이 모바일 네트워킹에 적용되면서 네트워크 슬라이스를 선택할 수 있는 메커니즘이 필수적이다. 5G 아키텍처에 대한 3GPP 표준 기술 사양에 따라 슬라이스 선택 프로세스를 활용하기 위해 Network Slice Selection Function (NSSF)가 포함되어 있다. 이 네트워크 기능의 실제 구현은 네트워크 인스턴스의 동적 변경 사항을 처리해야하므로 가상 네트워크 기능 (VNF)의 오케스트레이션을 지원하는 플랫폼이 필요하다. 제안 된 솔루션은 Central Office Rearchitected as a Data Center (CORD) 플랫폼에서 모바일 네트워크용으로 특화된 M-CORD를 사용하고 있다. 이는 서비스 오케스트레이터인 XoS를 통합하는 플랫폼 및 Software Defined Networking (SDN), Network Function Virtualization (NFV) 및 클라우드를 관리하는 OpenStack에 기반하고 있다. 이 플랫폼을 통해, 본 논문에서 제시된 NSSF 구현은 백엔드 서비스와 네트워크 기능 인스턴스 간의 동기화를 통해서 동적으로 슬라이스 정보를 얻을 수 있는 적절한 생태계를 제공하고 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권5호
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• pp.2267-2285
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• 2016

Information Centric Networking that uses content name instead of IP address as routing identifier can handle challenges such as traffic explosion and user mobility, but it also suffers from scalability and incompatibility problems. In this paper by combining the concept of software defined networking and Internet end to end arguments, we propose a wide area deployable software defined information centric networking service model named SD-ICN. SD-ICN employs a dual space structure that separates edge service network and core transmission network. The enhanced SDN techniques are used in edge service network in order to implement intelligent data routing and caching, while traditional IP technique is reserved in core transmission network so as to provide wide area high speed data transmission. Besides, a distributed name resolution system based on the cooperation of different controllers is also presented. The prototype experiments in our campus network show that SD-ICN can be deployed in a scalable and incremental way with no modification of the core network, and can support typical communication modes such as multicast, mobility, multihoming, load balancing, and multipath data transmission effectively.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2021년도 춘계학술대회
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• pp.94-96
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• 2021

기존 네트워크 아키텍처의 한계를 극복하기 위해 등장한 소프트웨어 정의 네트워킹(SDN)은 중앙 컨트롤러를 통해 라우팅 관리를 보다 간단하고 효율적으로 만든다. SR(Segment Routing)은 소스 라우팅을 수행하는 유연하고 확장가능한 방법으로 패킷 헤더에 정렬 된 세그먼트 목록을 통해 네트워크의 정보 경로를 정의한다. SDN을 사용하는 환경에서 각 라우터의 성능은 거의 동일하지만 라우팅 알고리즘에 따라 자주 활용되는 경로에 패킷이 집중되는 경향이 있다. 해당 경로에 있는 라우터는 고장의 빈도가 비교적 높고 병목현상이 발생할 가능성이 높다. 본 논문에서는 SR이 있는 SDN에서 네트워크 내 자원인 라우터가 패킷을 균등하게 처리하여 관리자 입장에서 유휴 라우터가 없이 네트워크 내의 자원을 활용함과 동시에 라우터의 관리를 수월하게 하는 라우팅 알고리즘을 제안한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권3호
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• pp.1063-1082
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• 2018

The concept of SDN (Software Defined Networking) endows the network with programmability and significantly improves the flexibility and extensibility of networks. Currently a plenty of research works on introducing SDN into wireless networks. Most of them focus on the innovation of the SDN based architectures but few consider how to realize the global perception of the network through the controller. In order to address this problem, a software defined carrier grade Wi-Fi framework called SWAN, is proposed firstly. Then based on the proposed SWAN architecture, a blueprint of introducing the traditional NSA (Network Situation Awareness) into SWAN is proposed and described in detail. Through perceiving various network data by a decentralized architecture and making comprehension and prediction on the perceived data, the proposed blueprint endows the controllers with the capability to aware of the current network situation and predict the near future situation. Meanwhile, the extensibility of the proposed blueprint makes it a universal solution for software defined wireless networks SDWNs rather than just for one case. Then we further research one typical use case of proposed NSA blueprint: network performance awareness (NPA). The subsequent comparison with other methods and result analysis not only well prove the effectiveness of proposed NPA but further provide a strong proof of the feasibility of proposed NSA blueprint.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권6호
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• pp.2848-2869
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• 2017

Mobile Wireless Sensor Networks (MWSN) are usually constrained in energy supply, which makes energy efficiency a key factor to extend the network lifetime. The management of the network topology has been widely used as a mechanism to enhance the lifetime of wireless sensor networks (WSN), and this work presents an alternative to this. Software Defined Networking (SDN) is a well-known technology in data center applications that separates the data and control planes during the network management. This paper proposes a solution based on SDN that optimizes the energy use in MWSN. The network intelligence is placed in a controller that can be accessed through different controller gateways within a MWSN. This network intelligence runs a Topology Control (TC) mechanism to build a backbone of coordinator nodes. Therefore, nodes only need to perform forwarding tasks, they reduce message retransmissions and CPU usage. This results in an improvement of the network lifetime. The performance of the proposed solution is evaluated and compared with a distributed approach using the OMNeT++ simulation framework. Results show that the network lifetime increases when 2 or more controller gateways are used.

• 한국IT서비스학회지
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• 제12권3호
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• pp.1-21
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• 2013

This study attempts to explain the mechanism behind the migration from vertically integrated value chain architecture to an innovation ecosystem consisting of horizontally separated layers in value chain. We first present a comprehensive framework based on the theoretical analysis of the drivers for migration to an innovation ecosystem, which are standard (institution), capability distribution, and transaction costs. The theoretical framework suggests that the migration to an innovation ecosystem is explained by the influence of standard on the evolutionary change of capability distribution and transaction costs. In particular, when the new de-jure standard competes with the de-facto standard, the new de-jure standard has the greatest impact on the distribution capabilities and the transaction costs. Based on this theoretical framework, we analyze the latest SDN (Software Defined Networking) case of the network industry. SDN standard has transformed the industry from a vertically integrated value chain architecture to a horizontally separated one with its influence on the distribution capabilities and the transaction costs in the industry.