• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.6
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• pp.387-396
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• 2014

Recently, there have been continuous efforts and progresses regarding the research on diverse network control and management platforms for SDN (Software Defined Networking). SDN is defined as a new technology to enable service providers/network operators easily to control and manage their networks by writing a simple application program. In SDN, incomplete or malicious programmable entities could cause break-down of underlying networks shared by heterogeneous devices and stake-holders. In this sense, any misunderstanding or diverse interpretations should be completely avoided. This paper proposes a new framework for SDN application verification and a prototype based on the formal method, especially with process algebra called pACSR which is an extended version of Algebra of Communicating Shared Resources (ACSR).

• ETRI Journal
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• v.42 no.2
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• pp.186-195
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• 2020

Software-defined networking (SDN) acts as a centralized management unit, especially in a network with devices that operate under the transport layer of the OSI model. However, when a network with layer 7 middleboxes (MBs) is considered, current SDNs exhibit limitations. As such, to achieve a real-centralized management unit, a new architecture is required that decouples the data and control planes of all network devices. In this report, we propose such a complementary architecture to the current SDN in which SDN-enabled MBs are included along with contemporary SDN-enabled switches. The management unit of this architecture improves network performance and reduces routing cost by considering the status of the MBs during flow forwarding. This unit consists of the following two parts: an SDN controller (SDNC) and a middlebox controller (MBC). The latter selects the best MBs for each flow and the former determines the best path according to its routing algorithm and provides information via the MBC. The results show that the proposed architecture improved performance because the utilization of all network devices including MBs is manageable.

• The Journal of Korean Institute of Next Generation Computing
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• v.15 no.4
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• pp.80-88
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• 2019

Software Defined Networking (SDN) is the future network paradigm of decoupling control and data functions. In SDN structure, it is hard to address scalability in case of large-scale networks because single controller managed thousands of switches in a centralized fashion. Most of previous studies have focused on horizontal scalability, where distributed controllers are assigned to network devices. However, they have abstracted the control plane and the application plane into a single controller. The layer of the common SDN architecture is divided into data plane, control plane, and application plane, but the control plane and application plane have been modeled as a single controller although they are logically separated. In this paper, we propose a analytical traffic model considering the both application plane and control plane based on queuing theory. This model can be used to address scalability issues such as controller placement problem without complicated simulations.

• Electronics and Telecommunications Trends
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• v.27 no.2
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• pp.129-136
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• 2012

OpenFlow 기술은 기존의 폐쇄적인 네트워킹 기술을 개방형 네트워킹 기술로 변화시켜서 새로운 네트워킹 기술 발전을 위한 기반을 제공하였다. OpenFlow 기술의 상용화 및 표준화를 촉진시키기 위해서 설립된 ONF(Open Networking Foundation)는 네트워킹 기술을 컴퓨팅 기술로 재해석하고 OpenFlow 기술을 기반으로 SDN(Software-Defined Networking) 기술을 정의하였다. SDN 기술은 네트워크 비용 및 복잡성을 근본적으로 해결하는 기술로, 기존 네트워킹 기술의 하드웨어 및 소프트웨어 기술을 근본적으로 변화시키는 미래인터넷 기술로 떠오르고 있다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.1
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• pp.29-43
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• 2019

In recent years, as the network traffic in the WSN(Wireless Sensor Network) has been increased by the growing number of IoT wireless devices, SDWSN(Software-Defined Wireless Sensor Network) and its security that aims a secure SDN(Software-Defined Networking) for efficiently managing network resources in WSN have received much attention. In this paper, we study on how to efficiently and securely design a PUF(Physical Unclonable Function)-assisted group key distribution scheme for the SDWSN environment. Recently, Huang et al. have designed a group key distribution scheme using the strengths of SDN and the physical security features of PUF. However, we observe that Huang et al.'s scheme has weak points that it does not only lack of authentication for the auxiliary controller but also it maintains the redundant synchronization information. In this paper, we securely design an authentication process of the auxiliary controller and improve the vulnerabilities of Huang et al.'s scheme by adding counter strings and random information but deleting the redundant synchronization information.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.1
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• pp.1-17
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• 2016

The separated management and operation of commercial IP/optical multilayer networks makes network operators look for a unified control plane (UCP) to reduce their capital and operational expenditure. Software-defined networking (SDN) provides a central control plane with a programmable mechanism, regarded as a promising UCP for future optical networks. The general control and scheduling mechanism in SDN-based optical burst switching (OBS) networks is insufficient so the controller has to process a large number of messages per second, resulting in low network resource utilization. In view of this, this paper presents the burst-flow scheduling mechanism (BFSM) with a proposed scheduling algorithm considering channel usage. The simulation results show that, compared with the general control and scheduling mechanism, BFSM provides higher resource utilization and controller performance for the SDN-based OBS network in terms of burst loss rate, the number of messages to which the controller responds, and the average latency of the controller to process a message.

• Information and Communications Magazine
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• v.32 no.7
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• pp.17-26
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• 2015

최근 네트워크 기술 동향에 있어서 이른바 핫 이슈 중 하나인 소프트웨어 정의 네트워킹(SDN, Software-Defined Networking)은 바야흐로 데이터센터, 기업, 캠퍼스 등의 근거리 데이터 네트워크(LAN, Local Area Network) 환경을 넘어서 통신망 사업자(캐리어)와 서비스 제공자를 통해 원거리 데이터 네트워크 (WAN, Wide Area Network)로 진화하고 있다. 본고에서는 종단간 SDN 프로덕션 서비스를 위한 소프트웨어 정의 원거리 네트워크(SD-WAN, Software-Defined WAN)의 개요 및 적용 사례를 소개하고, SD-WAN의 핵심 서비스 기술로 인식되고 있는 네트워크 최적화, 가상화, 자동화, SDX(Software-Defined Exchange) 등의 요소 기술과 연구 동향을 알아본다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.01a
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• pp.147-148
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• 2019

네트워크 응용 서비스들은 점점 더 복잡해지고 있으며, 네트워크 통신 기술의 발전과 함께 네트워크의 특성, 네트워크 관리 및 혼잡 제어에 대한 높은 요구 사항을 제시하므로 네트워크 트래픽 분류가 점점 더 중요해지고 있다. 트래픽 분류는 다양한 특성에 따라 네트워크 트래픽을 여러 클래스로 분류하여 처리하는 작업이다. 본 논문에서는 현재 네트워크 분야에서 적용된 여러 트래픽 분류 기법을 조사한다. 이를 통해 SDN(Software Defined Networking) 환경에서 효율적인 트래픽 분류가 가능한 기법 선택을 위해 비교하며 향후 연구를 위해 트래픽 분류 기법들을 소개한다.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.5
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• pp.817-824
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• 2021

The SDN(Software Defined Networking) technology, which appeared to overcome the limitations of the existing network system, resolves the rigidity of the existing system through the separation of HW and SW in network equipment. These characteristics of SDN provide wide scalability beyond hardware-oriented network equipment, and provide flexible load balancing policies in data centers of various sizes. In the meantime, many studies have been conducted to apply the advantages of SDN to data centers and have shown their effectiveness. The method mainly used in previous studies was to periodically check the server load and perform load balancing based on this. In this method, the more the number of servers and the shorter the server load check cycle, the more traffic increases. In this paper, we propose a new load balancing technique that can eliminate unnecessary traffic and manage server resources more efficiently by reporting to the controller when a specific level of load occurs in the server to solve this limitation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.11
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• pp.5179-5202
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• 2018

Transmission Control Protocol (TCP) is the most widely used protocol in the cloud data centers today. However, cloud data centers using TCP experience many issues as TCP was designed based on the assumption that it would primarily be used in Wide Area Networks (WANs). One of the major issues with TCP in the cloud data centers is the Incast issue. This issue arises because of the many-to-one communication pattern that commonly exists in the modern cloud data centers. In many-to-one communication pattern, multiple senders simultaneously send data to a single receiver. This causes packet loss at the switch buffer which results in TCP throughput collapse that leads to high Flow Completion Time (FCT). Recently, Software-Defined Networking (SDN) has been used by many researchers to mitigate the Incast issue. In this paper, a detailed survey of various SDN based solutions to the Incast issue is carried out. In this survey, various SDN based solutions are classified into four categories i.e. TCP Receive Window based solutions, Tuning TCP Parameters based solutions, Quick Recovery based solutions and Application Layer based solutions. All the solutions are critically evaluated in terms of their principles, advantages, and shortcomings. Another important feature of this survey is to compare various SDN based solutions with respect to different performance metrics e.g. maximum number of concurrent senders supported, calculation of delay at the controller etc. These performance metrics are important for deployment of any SDN based solution in modern cloud data centers. In addition, future research directions are also discussed in this survey that can be explored to design and develop better SDN based solutions to the Incast issue.