Earticle

SDN은 네트워크 장비의 제어 기능을 데이터 전달 기능과 분리하고 중앙 관리 시스템에 의해 관리되는 미래 네트워 크 기술로 다양한 네트워크 문제를 해결할 수 있다. 이러한 장점으로 SDN 도입은 여러 분야에서 고려되고 있으며, 모의 실험을 위해 주로 Mininet 시뮬레이터가 사용되고 있다. Mininet을 통해 빠르게 SDN 환경을 실험해볼 수 있으나 시스템의 안정성, 신뢰성 검증 실험, 실환경을 모사한 네트워크 실험을 수행하기에는 다소 부족하다. OPNET은 신뢰성이 입증된 네트워크 시뮬레이터로 SDN 모델을 지원하기 시작하였으나 아직 관련 연구가 전무하 다. 따라서 본 논문에서는 SDN M&S를 위한 두 시뮬레이터 간의 성능 비교 분석을 수행한다. 먼저 두 시뮬레이터 간 성능지표 비교를 위한 분석 모델을 제안한다. 효율적인 분석을 위하여 해당 모델에서는 토폴로지 모델 변환 방 법, 트래픽 생성 모델을 포함한다. 이 분석 모델을 통하여, Mininet과 OPNET에서의 처리량, 단대단 지연시간, 지 터 등 성능 지표를 비교하였다. Mininet은 처리량은 잘 반영하나, 지연시간이나 지터와 같이 네트워크 부하에 따른 변화를 제대로 반영하지 못하는 것으로 나타났다. 반면에 OPNET은 실제 네트워크 환경을 반영하고, 정밀한 네트 워크 분석 실험이 가능함을 보여주었다.

SDN is the future network paradigm of decoupling control plane and data plane by central controller system and helps to solve many networking problems. In general, Mininet is used for SDN　 simulation. Although it is possible to prototype virtual SDN networks fast with Mininet, it is not for stress testing to validate the stability and reliability and simulation suitable for real environment. OPNET, a well-known network simulator, has also released SDN model, but OPNET based SDN work is not published yet. In this paper, we compare performance parameters between two simulators. First, we propose the Comparative Analysis Model for efficiency including topology model converter and traffic generation model. Through this model, we compared throughput, End-To-End delay, and jitter between Mininet and OPNET. The Mininet shows the throughput performance very well, while it can not reflect the variations of dealy and jitter performances varying network loads. On the other hand, OPNET can reflect real network operational environements, and it also shows that it is desirable to carry out detail experiments for network analysis.

사전 M&S 성능 검증을 거쳐 개발 기간을 단축하고 성공률을 높인 ANASIS 사례를 봤을 때, 차기 군 위성통신체계에서 M&S 연구는 필수적이라 할 수 있다. 본 논문에서는 미군의 WIN-T SATCOM에서 채택한 MF-TDMA 기술을 OPNET 네트워크 시뮬레이터를 통해 모델링하였다. 기존의 군 위성통신체계에 대한 적용 가능성과 IP기반의 버스트(burst) 트래픽의 전송 가능성을 함께 확인하고자 했다. service level agreement (SLA)를 만족하는 QoS 관점에서 MF-TDMA가 차기 군 위성통신체계 접속 기술로 적합한 것으로 나타났다. 이 같은 M&S 검증을 통해 위성통신체계 실제 도입에 앞서 실현 가능성을 확인하고 앞으로 발생할 수 있는 문제점과 해결책을 마련하기 위한 M&S 플랫폼을 구축하고자 했다.

ANASIS M&S is a good example which shows that it shortens the development period and heightens the success. In the case of future military satellite communication systems, this M&S study is essential. In this paper, we model the MF-TDMA adopted in U.S. WIN-T SATCOM using OPNET network simulator. We intended to verify possibility of which MF-TDMA can be applied existing satellite system and MF-TDMA can support transport of IP based burst traffic. In terms of QoS satisfying SLA, MF-TDMA is suitable for future military satellite system. Through this M&S verification, we verified the realization possibility of satellite system and builded the M&S platform finding problems and solutions.

최근 인터넷 환경에 대한 사이버 공격 위협이 증가함에 따라 개인과 기업뿐만 아니라 국가 기반 시설까지 사이버 공격의 대상이 되고 있다. 민간 기업에서는 이러한 위협을 막기 위해 사이버 공격 보안 솔루션을 제시하고, 시뮬레이션 환경을 조성하여 공격 및 방어 기법을 분석하는 등 사이버 공격에 대한 효과적인 방어책을 마련하고 있다. 하지만 군 통신망에서는 이러한 사이버 공격을 방어하기 위한 시뮬레이션 환경이 제대로 조성되어있지 못하여 사이버전대책 수립에 어려움을 겪고 있다. 따라서 본 논문에서는 OPNET 시뮬레이터의 Cyber effect 모델을 이용하여 군유선통신망 사이버 공격 방어시뮬레이션 환경을 조성하고 대표적 사이버 공격인 DDoS 공격과 이를 방어하는 트래픽 측정 기반의 IDS를 모델링한다. 또한 모델링 된 공격, 탐지 모델에 대하여 실험을 통해 성능을 검증한다. 제안하는 유선 전술통신망 시뮬레이션 방법은 사이버전 모의를 위한 환경 모델 및 사이버 공격, 방어 모델을 정립하고 검증 가능한 기반을 마련하여 사이버전 기술발전에 기여한다.

Recently cyber attacks have increased threats to the Internet. Therefore, individuals and businesses, as well as national infrastructure to have been the target of cyber attacks. The private enterprise proposed a security solution for cyber attacks in order to prevent threats. Then, establish an effective defense against cyber attacks by creating a simulation environment for analyzing cyber attacks and defensive techniques. However, in tactical network, since the simulation environment for a cyber attack does not create properly. It makes difficult to establish defensive measures to cyber attack. In this paper, using the Cyber Effect model of OPNET simulator to create a simulation environment for the tactical wired network and not only modeling the DDoS attacks of typical cyber attacks but also, traffic measurement based IDS for detect the DDoS attacks. In addition, verifying the performance experiment against a the modeled attack and defense. The proposed idea model for establishing cyber warfare simulation and contributes to the cyber warfare technology.

A Mobile Ad hoc Network (MANET) is characterized by multi-hop wireless connectivity, frequently changing network topology with mobile nodes and the efficiency of the dynamic routing protocol plays an important role in the performance of the network. In this paper, the performance of five routing protocols for MANET is compared by using OPNET modeler: AODV, DSR, GRP, OLSR and TORA. The various performance metrics are examined, such as packet delivery ratio, end-to-end delay and routing overhead with varying data traffic, number of nodes and mobility. In our simulation results, OLSR shows the best performance in terms of data delivery ratio in static networks, while AODV has the best performance in mobile networks with moderate data traffic. When comparing proactive protocols (OLSR, GRP) and reactive protocols (AODV, DSR) with varying data traffic in the static networks, proactive protocols consistently presents almost constant overhead while the reactive protocols show a sharp increase to some extent. When comparing each of proactive protocols in static and mobile networks, OLSR is better than GRP in the delivery ratio while overhead is more. As for reactive protocols, DSR outperforms AODV under the moderate data traffic in static networks because it exploits caching aggressively and maintains multiple routes per destination. However, this advantage turns into disadvantage in high mobility networks since the chance of the cached routes becoming stale increases.

A Mobile Ad hoc network (MANET) is a network consisting of a set of wireless mobile nodes, which communicate with each other without centralized control or established infrastructure. In this paper, to obtain a better understanding of AODV (Ad hoc On-Demand Distance Vector Routing Protocol) and OLSR (Optimized Link State Routing Protocol) routing protocols, different performances are simulated and analyzed using OPNET modeler 14.5 with the various performance metrics, such as packet delivery ratio, end-to-end delay and routing overhead. As a conclusion, in static analysis, the routing overhead of OLSR is affected by the number of nodes, but not data traffic. In AODV case, it is affected by both data traffic and number of nodes. In mobility analysis, routing overhead is not greatly affected by mobility speed in AODV and OLSR, and the PDR (Packet Delivery Ratio) of OLSR is decreased as the node speed increased, while AODV is not changed. As to delay, AODV is always higher than OLSR in both static and mobility cases.

Vehicle Ad hoc Network are composed of the vehicle with wireless communication equipment, road construction collecting base station transmission network, background processing server and related acquisition and processing software system. Based on Internet of things simulation console, this paper designs vehicle to vehicle scenarios of Intelligent Transportation System, simulates its communication process , analyzes the simulation data of sending and receiving, evaluates the entire performance of the network, which can offer reference to designing and optimizing the Vehicle Ad hoc Network. In this paper we try to prove: In the low speed motion in vehicle to vehicle scenario of Vehicle Ad hoc Network, as the routing protocol in the network layer, AODV protocol is much better than DSR protocol.

Against the backdrop of Internet of Things on campus, this paper makes Internet of things cover the entire campus through wired and wireless accesses. As a result, campus sees the fulfillment of information transfer via computers, mobile phones, devices and other articles, which is the embodiment of intelligence. Besides, OPNET is used for modeling and simulation of wireless network structure in SDN intelligent campus, with a view to analyzing the feasibility and advantages of various campus network topologies. Then, a reasonable scheme is presented responding to different types of topologies, which is conducive to better building an intelligent campus.

Wireless sensor networks are set of connections of nodes comprising of several sensor nodes connected to every additional in the course of a wireless environment. Wireless sensor nodes consists of some composite functions such as the detection of signals, collection of signals and data, deviousness and routing of nearby data by implanting them either randomly or by following a specific approach into various areas. In the present paper, the IEEE 802.15.4 protocol was considered which can be used vastly in communication networks. The performance of this protocol was analyzed in this paper through graphical representation. It consists of various useful standards for communication with respect to the wireless sensor network considerations like usage of battery for applications by sensors, the power consumption by various sensors should be low, they provide very extraordinary performance over sensors which works at very short distance and makes it likely to use nearly various frequency bands in the real time applications. The present simulator we had considered was RIVERBED Academic Edition 17.5, which is proficient of producing precise outcomes and gives user a detailed analysis of results which helps in identifying the actual behavior of the real system for real time applications or user designed applications. By using this simulator program, the performance of the network with respect to throughput of the nodes with number of nodes was analyzed which helps in designing a new real time network.

Recently wireless sensor Network (WSN) and wireless personal area network (WPAN) has gained lot of interest from the research community because of its diverse applications of controlling, monitoring and automation of home, offices or any rescue area. Zigbee based on IEEE 802.15.4 standard is key enabling technology for the success of both WSN and WPAN. Zigbee has some inherent powerful characteristics like very low power consumption, localization and low cost that has drawn the attention of research community recently. Along with merits come the challenges for the success of Zigbee based networks at various layers of the network model. Network topologies in Zigbee are to be selected based on applications and performance requirements. So this paper investigates the performance of Zigbee for tree and mesh topologies. In doing so parameters like MAC throughput, MAC load, MAC delay, end to end delay have been evaluated through extensive simulations using OPNET. The intricate behavior of these topologies in Zigbee shows optimum bounds of performance for these topologies have been computed in this work

본 논문에서는 이동망에서 통신노드가 다이나믹하게 이동하는 경우, VLC 음성품질을 위지하기 위한 상호연동 구조를 다룬다. 연동구조에서 체계적인 품질 분석은 OPENT 시뮬레이터를 사용하였으며, 패킷지연율과 성능분석으로 결과를 제시하였다. 실험결과에 따라 이동노드의 수가 작을 때, PDR은 상대적으로 데이터 프래픽이 증가함에 따라 안정을 유지하며, 성능은 이동노드의 수에 영향을 받는다. 특히 MANET 노드 밀도가 크게 증가하면, 성능은 높아지지만 이동속도에 영향을 받지 않았다. 또한 FTP 업다운 응답시간은 이동속도와 노드의 수에 크게 영향을 주지 않음을 확인하였다.

This paper represents an interworking architecture for keeping the VLC audio quality between Worldwide Interoperability for Microwave Access (WiMAX) and IEEE 802.11 Mobile Ad hoc Network (MANET) where both mobile routers and mobile nodes are moving dynamically. Systematic performance analysis on the interworking architecture has been conducted by using OPNET simulator to show the results such as Packet Delivery Ratio (PDR) and throughput. Based on simulation results, when the number of MANET nodes is small, PDR remains relatively stable even though data packets increase. However, with the many MANET nodes, PDR decreases as data traffic increases. Throughput is affected by the number of MANET nodes. Especially when the MANET node density has increased further, throughput is much higher, but it is not affected by the mobility speed. However, FTP download and upload response time is not affected much by both the number of MANET nodes and the mobility speed.

The paper aims to investigate the performance of the TCP variants in MANET and its behavior with respect to different routing protocols. In the performance evaluation two different routing protocols On-Demand Distance Vector (AODV) and Optimized Link State Routing (OLSR) have been considered with three different TCP variants Tahoe, Reno and New-Reno. Different scenarios that can achieve scalability, mobility and http traffic loading investigation in MANET have been considered in the evaluation. Depending on the variables delay and throughput the performances parameters of the routing protocols are graded. Conclusions are drawn based on the evaluation results using OPNET simulator. The results clearly show that the both AODV and OLSR achieve acceptable performance. However, the merits of AODV over OLSR or vise versa depend on the network environment such as TCP variant used, traffic load, number of nodes and mobile speed together with the required parameter in the evaluation delay or the throughput. The results clearly demonstrate that the AODV and OLSR achieve the same performance under low http traffic, small size network and low mobile speed. However, as the network size increases the OLSR achieves higher throughput whereas AODV achieves lower delay. The effect of Taho, Reno and New-Reno is small compared with the effect of routing protocol. Thus the paper recommends the use of expert system that can choose the optimum routing protocol for the required condition.

Loads of research work and efforts have been done since last decade to provide support and solution to different problems and challenges related to mobile ad hoc networks. But still the fast growing technology needs attention in many areas such as routing, bandwidth, security, power consumption, collisions, simulations, and topology control due to moving nodes. In mobile ad hoc network we cannot use the existing techniques for better quality as we are using in fixed wireless network for better efficiency. In this paper we not only compare the performance of ad-hoc routing protocols in order to prove its correctness, efficiency, traffic load and end to end delay in dynamic intermediate nodes senario but also to implement OPNET simulator in AODV and DSR routing protocols. we proposed OPNET simulator to check performance with respect to different parameters that mobility model changes have a significant impact on their performance in different ways to support QOS. By proposing OPNET which results the combined performance of both AODV and DSR routing protocol could be best solution for routing in MANET, instead of separate performance of both AODV and DSR and also in intermediate nodes data transfer rate from source to destination.

본 논문에서는 OPNET 시뮬레이터를 사용하여 IEEE 802.16e(모바일 WiMAX)와 IEEE 802.11e(WLAN) 무선망 상호접속 구조에서의 서비스품질에 대한 체계적 성능분석을 수행하였다. OPNET 시뮬레이터를 이용해 4가지 이동 시나리오에서 음성 트래픽을 인가하는 경우에 대한 시뮬레이션이 수행되었으며, MOS값, 종단간 지연시간, 패킷 전달률 등과 같은 다양한 성능지표들이 분석되었다. 시뮬레이션 결과 MOS 값의 경우 단말이 정지/이동하는 두 경우 모두 WiMAX-> WiMAX 이동 시나리오가 가장 좋은 결과를 보였다. 반면에 종단간 지연시간은 4가지 이동 시나리오 모두 단말의 이동에 의해 크게 영향을 받지 않았다. 그러나 특히 WLAN->WLAN 이동 시나리오의 경우 단말의 이동성은 MOS값과 패킷 전달률에 많은 영향을 미치는 것으로 나타났다.

This paper addressed the implementation of the systematic performance analysis of Quality of Service (QoS) by using OPNET simulator in the interworking architecture of IEEE 802.16e (mobile WiMAX) and IEEE 802.11e (WLAN) wireless network. Four simulation cases were provided in OPNET simulator and a voice traffic was simulated with various performance metrics, such as Mean Opinion Score (MOS), end-to-end delay and packet transmission ratio. Based on the simulation results, the MOS value presented better in WiMAX to WiMAX case compared to others in both static and mobility case. Meanwhile, end-to-end delay was not greatly affected by mobility in four cases. However, mobility was affected much in MOS value and packet transmission ratio in WLAN to WLAN case than in others.

최근 지능형전력망 산업에 이어 최근 IoT, 마이크로그리드 등 전력시스템의 고도화 및 활성화를 위해 다양한 분야의 접목이 시도되고 있다. 하지만 이러한 전력시스템의 진화가 생각보다 느리게 진행되는 이유는 시스템 자체의 신뢰성이 부족한 부분이 있지만, 수용가, 즉 소비자들의 신뢰를 확보하지 못한 부분 역시 간과하기 힘들다. 본 논문에서는 수용가 측 지능형 전기설비에 대한 신뢰성을 확보하기 위한 방안 중 하나로 적합성평가를 위해 OPNET을 활용한 저압 전기설비의 적합성평가 방법을 모의하였다.

이동통신망의 규모나 서비스 등이 기하급수적으로 증가하기 때문에 데이터 트래픽에 대한 정확한 특성분석은 매우 어렵지만, 트래픽 특성분석이 망 설계나 운용에 상당한 영향을 미친다는 점을 고려하면, 데이터 트래픽 모델링에 대한 연구는 가장 기본적으로 이루어져야 할 사항이라 할 수 있다. 따라서 본 논문에서는 데이터 트래픽에 대한 특성을 분석하기 위해 cdma2000 시스템의 국제적인 표준화 단체인 3GPP2에서 언급한 HTTP, FTP, WAP, Near Real Time Video 트래픽에 대한 트래픽 특성을 분석하여 자기 유사성(Self-similarity)을 가짐을 입증하였다.

Ethernet PON(Passive Optical Network)에서 핵심 기술 중의 하나인 MAC(Media Access Control) 프로토콜은 ONU(Optical Network틴nit)들이 상향으로 트래픽을 전송할 때 공유되어 있는 링크상의 충돌을 방지하고, 효율적인 대역폭을 할당하기 위한 스케줄링 알고리즘을 포함하고 있다. 본 논문에서는 차세대 가입자 망인 Ethernet PON에서 상향으로의 대역폭 부족을 개선하기 위하여, n개의 파장을 사용한 가변 슬롯 할당 TDMA(Time Division Multiple Access) 방식의 MAC 프로토콜을 제안한다. 이를 검증하기 위하여 OPNET 시뮬레이션 도구를 이용해 Ethernet PON 모델을 설계하고 시뮬레이션 한다.

본 논문에서는 무선 근거리 네트워크 (Wireless Personal Area Network : WPAN) 환경에서 Koinonia 라는 새로운 시스템을 제안하고 링크계층에 적응형 계층을 추가하여 구성 및 모델링 함으로써 2.4GHz의 ISM 무선 대역을 이용하여 근거리에 위치한 무선 기기들을 연결하고 음성정보 및 데이타를 전송하는 근거리 무선 네트워크 시스템의 시뮬레이터를 구현 함을 목적으로 하였다.

Ethernet PON(Passive Optical Network)은 최근 들어 활발하게 연구되고 있는 경제적이고 효율적인 가입자망 구조이다. 본 논문에서는 OPNET 시뮬레이션 도구를 사용하여 Ethernet PON 시뮬레이션 모델을 구현하고, 시뮬레이션 한다. OLT(Optical Line Termination)에 연결되는 ONU(Optical Network Unit)의 개수, 트래픽 및 네트워크 파라미터에 대한 ONU의 버퍼 크기(buffer size)를 분석하고, 이 결과로서 실제 네트워크에 적용할 효율적이고 적정한 ONU의 버퍼 크기를 제안한다.