Earticle

본 논문은 자율주행차량 환경에서 V2X(Vehicle-to-Everything) 통신의 성능을 최적화하고, 높은 이동성과 네트워크 불안정성이 특징인 VANET(Vehicular Ad Hoc Network) 환경에서 효과적인 지능형 교통 시스템(ITS)을 구현하기 위한 SDVN(Software-Defined Vehicular Network) 기반 설계 방법을 제안한다. 기존의 VANET은 분산형 구조로 인해 패킷 손실, 지연 증가, 네트워크 단절 등 여러 한계가 존재하며, 이를 해결하기 위해 본 연구는 SDN 아키텍처를 차량 통신망에 통합하였다. SDN의 중앙집중 제어 특성을 활용하여 네트워크 토폴로지를 실시간으로 관리하고, 트래픽 상황에 따라 최적의 경로를 동적으로 설정할 수 있도록 하였다. 시뮬레이션은 VEINS, SUMO, OMNeT++, Mininet-WiFi, Ryu 컨트롤러를 통합하여 구축되었으며, 다양한 차량 밀도와 도시 교차로 기반 시나리오에서 VANET 대비 SDVN의 성능을 정량적으로 비교하였다. 실험 결과, SDVN 기반 ITS는 평균 지연 시간에서 최대 25% 감소, 패킷 전달률(PDR) 15% 증가, 네트워크 처리량(Throughput) 약 30% 향상을 나타냈으며, 중앙제어로 인한 제어 메시지 오버헤드는 소폭 증가하였다. 본 연구는 향후 자율주행 기술의 확산과 더불어 차량 통신 인프라의 고도화를 위한 기반 기술로 활용될 수 있을 것이다.

This paper presents an in-depth optimization strategy for Vehicle-to-Everything (V2X) communication tailored for autonomous vehicle networks and proposes a robust Intelligent Transportation System (ITS) architecture built upon Software-Defined Vehicular Networking (SDVN) within highly dynamic VANET environments. While traditional Vehicular Ad Hoc Networks (VANETs) offer decentralized communication among mobile nodes, they suffer from inherent limitations such as frequent topology changes, high latency, and unreliable data delivery. The proposed architecture integrates real-time mobility simulation (SUMO), discrete event network modeling (OMNeT++), vehicular communication (VEINS), wireless emulation (Mininet-WiFi), and programmable flow control via the Ryu SDN controller. Various urban traffic scenarios with differing vehicle densities (low, medium, high) were simulated, and the performance of the SDVN-based ITS was benchmarked against a conventional VANET model. The SDVN model demonstrated a reduction of up to 25% in latency, a 15% improvement in PDR, and up to 30% higher throughput, while incurring only a moderate increase in control overhead due to SDN signaling. These findings validate the feasibility and efficiency of SDVN-enhanced ITS frameworks for next-generation smart transportation infrastructures and offer valuable insights for large-scale deployment in future autonomous mobility ecosystems.

The advanced IEC 61850 smart transformer has shown an improved performance in monitoring, controlling, and protecting the equipment in smart substations. However, heterogeneity, feasibility, and network control problems have limited the smart transformer’s performance in networks. To address these issues, a software-defined networking model was proposed using ISO/IEC/IEEE 21451 networks. An IEC-61850-based network controller was designed as a new kind of intelligent electrical device (IED). The proposed data and information models enhanced the network awareness ability and facilitated the access of smart sensors in transformer to communication networks. The performance evaluation results showed an improved efficiency.

With the rise of bandwidth-intensive applications, such as video streaming and cloud services, efficient routing decision networks have become increasingly important. Bandwidth allocation issues arise from various causes. This paper examines the Bandwidth Starvation Problem (BSP), where routing decisions that insufficiently account for low-demand flows hinder high-demand flows. Current Reinforcement Learning (RL)-based hop-by-hop routing methods overlook bandwidth demand factors, worsening the BSP. We propose a bandwidth demand-oriented reward function and a Deep Reinforcement Learning (DRL) framework to address this challenge. Experiments on Topology Zoo topologies demonstrate proposed approach enhances throughput, utilization, and maximum service capacity over existing methods.

Recently, Software-defined networking (SDN) is emerging and intensively discussed as one of the most promising technologies to make networks programmable and virtualizable, so that SDN could simplify network operations, reduce cost, and accelerate service delivery. Even if openness which gives network customers choice to build best-of-breed their networks is one of main properties of SDN, open architecture, interfaces, APIs, etc. are not fully investigated yet. In this paper, we present SDN reference architecture for open networking environment, including programmable control plane, languages and formal specification, and data plane abstraction. In addition, we discuss some of open questions related to SDN architecture and standardization issues.

It is essential to support real-time communication in networked control systems, such as automotive systems or smart factories. Several studies have been conducted to schedule real-time flows by adjusting their priorities using software-defined networking (SDN). However, because its architecture was not originally designed for realtime communication, unexpected challenges may occur if it is utilized without careful consideration. In particular, because SDN does not provide an atomic method for priority adjustment, some flows may violate their timing constraints by receiving additional interference during priority adjustment. In this paper, we propose a novel scheme to safely update the flow priorities in SDN-based real-time systems. Accordingly, we first analyze the challenge that may occur when adjusting flow priorities within a switch. We then develop a scheme that determines safe procedures for priority adjustment. By network emulations, we demonstrate that the above challenge occurs in 178 out of 300 flow sets, but our scheme can effectively prevent all of them.

In this paper, an Intent-based networking Framework is proposed leveraging the central controller intelligence premise of software-defined networking (SDN). The quality-of-service (QoS) is provisioned according to the application service request priorities by the SDN controller. To achieve this, in this paper, we use the Analytic hierarchy process (AHP) as a module on the SDN controller for intent-based routing. An AHP module employed at the SDN controller prioritizes the application objectives and overarching parameters to compute the route from source to destination. The AHP module at the SDN controller prioritizes the application service priorities, and the SDN controller will compute the route according to the intents from the AHP module. The controller will prioritize the intents of the applications according to the eigen priority vector obtained for that application service requests from the AHP module according to the criteria priority values.

멀티캐스트 전송 방식은 현재 오디오, 비디오등과 같은 멀티미디어 데이터를 전송하는 IPTV와 스마트가전과 같은컨버젼스 분야에도 많이 응용되고 있다. 현재 서비스 가입자의 증가와 데이터의 폭증으로 인해 여러 서비스에서 효율적이고 데이터 신뢰성이 높은 멀티캐스트 전송 방식에 대한 시장의 요구가 높아지고 있다. 멀티캐스트 트래픽에대한 모니터링이 수반되어, 손실이 자주 일어나는 링크를 우회하는 경로를 설정하는 연구들이 수행되어야 어플리케이션 별로 특화된 경로설정이 가능하게 된다. 패킷 손실 구간을 탐지하기 위하여 라우터의 수정이 필요하지만, 기존의 분산적/폐쇄적 네트워크의 특징 때문에, 장비제어 프로토콜의 개발이 어려웠으며, 네트워크 장비 회사에서 제공하는 네트워크 관리 소프트웨어를 제외하고는 학술적 연구가 많이 되어 있지 않다. 본 논문에서는 SDN(Software Defined Network) 기술을 이용하여 멀티캐스트 전송 네트워크에서 라우터와 컨트롤러의 통신을 통해 패킷이 손실된 위치를 파악할 수 있는 방식에 대해 제안한다. 기존의 전통적인 방식은, 패킷의 손실 발생 이후의 라우터들로부터 중복된 오류 보고 메시지를 다수 수신하게 되며, 이 중복된 메시지는 손실 위치를 파악하는데 오류를 발생시키는데 비하여, 본 논문에서 제안하는 방식은 패킷 손실이 발생된 구간에서만 오류 보고 메시지를 받게 되어 위치 파악 오류를 최소화한다.

Multicast is used in the field of convergence, such as IPTV, transmitting video, audio, and smart appliances. Since the number of service user and the data they use increases highly, effective and reliable transmission method is required. It is required to monitor the multicast traffic to provide a proper routing service to a specific application. Due to a closed and distributed character of the legacy network, it is difficult to design a protocol which requires the modification of network devices. Thus there has been a few research work on this multicast traffic monitoring topic except the monitoring software provided by some network device manufactures. In this paper, we propose an effective multicast network management method using SDN. We propose the method that can find out where the packet loss has been occurred and prevent a possible path detection error caused by duplicated packet loss reports which are common in the general approach. Our method which uses a fake packet removes the duplicated error reports, thus it will minimize the error on the packet loss path detection.

무선 센서 네트워크는 자원 제약적인 센서 노드들로 구성되는 네트워크로, 분산 서비스 거부 공격, 라우팅 공격 등 다양한 악의적인 공격이 발생될 수 있다. 본 논문에서는 소프트웨어 정의 네트워킹 기술과 보안 기술을 융합하여 무선 센서 네트워크에 발생하는 다양한 공격을 탐지하고 방어하는 기법을 제안한다. 제안 기법에서는 서버에 있는 침입 탐지 및 방지 시스템이 SDN 컨트롤러를 통해 전달되는 오픈플로우 스위치의 로그 정보들을 축적하여 침입을 탐지하며, 침입을 탐지했을 때 오픈플로우 프로토콜을 이용하여 오픈플로우 스위치에 해당 침입에 대한 대응방안을 설정함으로써 침입을 방지할 수 있다. 본 논문에서는 분산 서비스 거부 공격 및 라우팅 공격 발생 시 침입 탐지 및 방지를 보임으로써 제안기법의 타당성을 보였다. 제안기법은 다른 기법과 달리 중앙 집중 서버에서 그래프 모델과 침입 탐지 모델을 융합하여 효과적이고 메시지 효율적으로 다양한 침입을 탐지하고 방지할 수 있다.

A wireless sensor network is composed of many resource constrained sensor nodes. These networks are attacked by malicious attacks like DDoS and routing attacks. In this paper, we propose the intrusion detection and prevention system using convergence of software-defined networking and security technology in wireless sensor networks. Our proposed scheme detects various intrusions in a central server by accumulating log messages of OpenFlow switch through SDN controller and prevents the intrusions by configuring OpenFlow switch. In order to validate our proposed scheme, we show it can detect and prevent some malicious attacks in wireless sensor networks.

소프트웨어 정의 네트워킹(SDN)은 네트워크 장치의 데이터 기능과 제어기능을 분리한 미래 네트워킹 기술이다. 네 트워크 장치들이 하나의 컨트롤러에 의해 중앙 제어되는 SDN의 구조는 대규모의 네트워크로의 확장성을 보장하기 가 쉽지 않다. 선행연구들은 다수의 컨트롤러를 배치하는 수평적 확장성에 초점을 두어왔다. 이 연구들은 제어 평면 과 응용 평면을 하나의 컨트롤러로 추상화하고 있다. 보편적인 SDN 아키텍처의 계층은 데이터 평면, 제어 평면, 응용 평면으로 나뉘는데 응용평면과 제어평면은 논리적으로 분리되어 있음에도 두 평면을 하나의 컨트롤러로 간주하 였다. 따라서 본 논문에서는 대기행령 이론을 바탕으로 제어 평면과 응용 평면을 분리하여 반영한 트래픽 성능 분석 모델을 제안한다. 이 모델을 사용하면 복잡한 시뮬레이션 대신 간단하게 컨트롤러 배치 문제 등과 같은 확장성 문제에 활용할 수 있다.

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.

As for Software-Defined Networking (SDN), an additional management plane may possibly be of great significance besides the control plane and the data plane. However, the implementation of this management plane is not yet mature. Thus in this case, study on the management plane is of great importance for management issues of SDN. This paper then aims to promote the implementation of the management plane for SDN, by studying the SDN management roles, proposing the framework of the management plane for SDN, discussing the SDN management operations, and utilizing the queuing theory for SDN management. Simulation results validate that, the proposed queuing model for the management plane of SDN prospects a feasible way to understand the queuing principles between management applications and the SDN manager.

Nowadays, Software-Defined Networking (SDN) is utilized to improve network management, but the management standardization of SDN itself is still under development. This paper focuses on the integration problem of management information models for SDN, and in order to understand the principles of unified information modeling for SDN management, it tries to apply the theory of concept lattices to learn concept hierarchy from the YANG language for SDN management. Thus, this paper first obtains formal contexts from YANG statements, and then studies formal concepts from the viewpoint of posets so as to learn concept hierarchy from YANG. Case study shows that, the proposed approach is feasible and promising to promote unified information modeling for SDN management.

When considering the coexistence of Software-Defined Networking (SDN) and non-SDN, unified management of SDN calls for study on both the information representation and the communication pattern. This paper first proposes the use of the extension theory in order to formally define management information of SDN in a unified manner. And this paper then introduces the concept of unified manager to the communication pattern for unified management of SDN, and considers application of the queuing theory from the perspective of the basic queue and the queue spaces. Finally, simulation results validate that, proposed approach based on the queuing theory is feasible for unified management of SDN from the viewpoint of the communication pattern.

Since the separation of the control plane and the data plane for Software-Defined Networking (SDN) leads to more and more security threats on the control plane and the SDN controllers, issues related to threat detection and defense of SDN must be seriously considered. This paper tries to introduce Extenics into the research on threat detection and defense of SDN and proposes an extension approach from a formal viewpoint. It first uses the matter-elements and the composite-elements to formally represent four security-related roles of SDN. It then utilizes the extension theory and basic-elements, by applying the dependent function to threat detection of SDN and making use of the affair-elements to formalize the NETCONF operations for threat defense of SDN. Finally, case study validates the feasibility of proposed extension approach in promoting the formalization of not only the security-related roles of SDN but also threat detection and defense of SDN.

Software-Defined Networking (SDN) is a new-generation network that decouples the control plane and the data plane, and an additional management plane still lacks a mature implementation solution. In this case, monitoring service level parameters is of great significance to study issues related to service management for SDN. This paper then aims to apply the queuing theory and the extension theory to monitor service level parameters of SDN and propose an integrated approach based on both two theories from the formalization point of view. Simulation result and scenario analysis validate that, the proposed integrated approach prospects a feasible way of formalizing the solution to monitor service level parameters of SDN.

Software Defined Networking (SDN) is an open source networking framework recently introduced. It allows developers to program and reprogram the network so that intelligence and new features can be integrated to optimize and enhance the performance of the network. This paper is focused on optimizing the routing implementation of SDN (i.e. SDN Controller). We have used the Floodlight Open Source SDN Controller1 in our experimentation. The Floodlight controller provide source Java libraries and APIs.. It uses Dijkstra’s algorithm to calculate the shortest path between any source and any destination within the network. However, the default routing implementation of Floodlight Controller is such that, while calculating any path, it ignores the actual bandwidth of the link as it takes a unit value for each link. The resultant calculated path becomes a least hop path. This least hop path may be an optimal path where all the links in the network have equal bandwidth and may not be optimal where the networks have unequal link bandwidth. However, today’s networks are mostly consisting of unequal link bandwidth. The goal of this paper is to re-structure the Floodlight Controller so that it can collect the actual bandwidth of all the links in the network and use this information to calculate

현재의 OpenFlow 기반의 SDN(Software-Defined Networking) 기술은 데이터 센터 네트워크를 대체하기 위한 기술로 간주되고 있으며 캐리어(통신 사업자)의 네트워크에 적용하기에는 아직 많은 기술 개발이 필요한 것으로 알려져 있다. 본고에서는 캐리어 네트워크에 적용 가능한 SDN을 SDN 2.0으로 정의하고 SDN 2.0의 실현에 필요한 주요 기술들의 연구동향과 적용방안에 대해 살펴본다.

클라우드 컴퓨팅 기술의 핵심은 데이터 센터이며 데이터 센터 내에서는 네트워킹 기술이 중요하다. 클라우드 데이터 센터에는 수만에서 수십만 개의 물리적 서버로 구성되어 있어서 높은 수준의 데이터 전송이 가능한 네트워킹 기술이 필요하다. 이러한 네트워킹 기술은 또한 확장성과 고장 감내성 등이 필요하며 민첩성이 필요하다. 이를 위해 다양한 다중 경로를 이용하는 기법이 제안되었다. 하지만 주로 부하 균형을 위한 기법이나 임의적으로 경로를 선택하는 데 사용되었다. 본 논문에서는 소프트웨어 정의 네트워킹 기술을 이용하여 다중 경로를 구성하고 다중 경로를 이용하여 트래픽을 병렬 전송함으로써 빠른 전송속도를 가져오며, 확장성 문제를 해결하고 고장 발생 시에 감내할 수 있는 기술을 제안한다.

The core of the cloud computing technology is the data center in that the networking technology is important. Cloud data centers are comprised of tens or even hundreds of thousands of physical servers, so networking technology is required for high-speed data transfer. These networking technologies also require scalability, fault tolerance, and agility. For these requirements, many multi-path based schemes have been proposed. However, it was mainly used for load balancing of traffic and select a path randomly. In this paper, a scheme that can construct a multipath using software defined networking technology and transmit the traffic in parallel by using the multipath to achieve a fast transmission speed, solve the scalability problem and fault tolerance is proposed.

하나의 AP에 다수의 사용자가 연결되어 AP의 부하가 가중될 경우 해당 AP에 연결되어 있는 사용자들의 무선데이터 전송속도는 현저하게 떨어진다. 이를 방지하기 위해 본 논문에서는 SDN 기술을 사용하여 SDN 제어기에서 연결된 AP들의 부하분산을 지원하는 시스템을 제안하였으며, 해당 시스템은 SDN 제어기와 AP 그리고 안드로이드 스마트폰으로 구성되었다. 본 논문에서 제안하는 시스템을 지원하기 위해 각각의 AP들은 SDN 제어기와의 통신을 담당하는 SDN Agent를 설치한다. 또한 현재 이동통신단말기가 연결이 가능한 AP들의 목록을 작성하기 위해 이동통신 단말기에도 SDN Agent를 설치한다. SDN 제어기는 각각의 Agent로부터 받은 정보들을 통해 적합한 AP로 이동통신 단말기가 다시 연결될 수 있도록 한다. 본 논문에서는 제안한 시스템의 검증을 위해 실험환경을 구성하여 실험을 수행하였으며 효과적으로 동작하는 것을 확인하였다.

소프트웨어 정의 네트워킹(SDN, Software-Defined Networking) 기술은 기존의 네트워크 장비와는 다르게 중앙 집중화된 SDN 컨트롤러가 다수의 스위치를 관리하여 어떠한 네트워크 요구사항도 쉽게 적용할 수 있는 차세대 네트워크 기술이다. 하지만 최근 몇 년간 SDN에 대한 연구가 급격하게 진행되면서 이에 대한 보안 문제도 중요하게 여겨지고 있다. 따라서 본 논문에서는 SDN에서 가능한 주요 보안 문제들을 조사하고, 이를 해결할 수 있는 방안으로 블록체인(Blockchain) 기술을 SDN에 적용할 수 있는 방법론을 소개한다.

Software-Defined Networking, called SDN is a next-generation network technology that allows a centralized SDN controller to manage multiple switches and easily apply any network requirements, unlike traditional network devices. However, as the research on SDN has progressed rapidly in recent years, the security of SDN is also considered to be important. Therefore, in this paper, we investigate the major security problems in SDN and introduce a methodology to apply blockchain technology to SDN as a solution to solve them.

최근 네트워킹 분야에서 활발히 연구되고 있는 SDN(Software-Defined Networking) 기술에서, 보다 편리하고 정확한 방법으로 네트워크를 구축하기 위한 SDN 프로그래밍 기술에 대해 최근 발표된 논문을 중심으로 연구 동향을 분석한다.