• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.95-98
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• 2010

OpenFlow 는 인터넷 스위치(라우터 포함)를 부분적으로 개선하여 연구자가 기존 네트워크의 정상적인 서비스를 간섭하지 않으면서 새로운 네트워킹 기술을 테스트할 수 있는 미래인터넷 (Future Internet) 연구를 위한 프로토콜이다. 하지만 OpenFlow 기반 테스트베드의 상태 정보를 확인하고 발생한 플로우들을 제어할 수 있는 도구(tool)가 부족하여, 연구자가 실험의 다양성을 제공 받기 어렵다. ENVI(Extensible Network Visualization & Control Framework)는 OpenFlow 네트워크 가시화를 위한 프레임워크로, 사용자의 목적에 맞는 인터페이스를 만들도록 제공해 준다. 본 논문에서는 OpenFlow 기반 테스트베드의 토폴로지 정보 및 플로우 상태를 쉽게 확인하고, 플로우 경로를 제어하는 OpenFlow 제어기 응용의 개발과 ENVI 의 확장을 설계하고 이를 구현을 통해 검증한다.

• Journal of KIISE:Information Networking
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• v.41 no.4
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• pp.167-176
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• 2014

In this paper, we discuss the implementation and experimentations of a new future Internet architecture for mobile-oriented environments, named Mobile Oriented Future Internet (MOFI). The MOFI architecture is featured by the host identifier and local locator for identifier-locator separation, Query-First Data Delivery (QFDD), and Distributed Mapping System (DMS) for identifier-locator mapping control. In the existing study on MOFI, we examined the intra-domain mobility control, the implementation of MOFI over Linux platform, and the performance analysis over the small-scale testbed. In this paper, we describe how to implement the MOFI architecture for inter-domain mobility control by using the OpenFlow and Click Modular Router platform. From the experimentations over the KOREN testbed, we can see that the MOFI scheme can give better performance than the existing Proxy Mobile IP scheme.

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.07a
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• pp.275-276
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• 2015

네트워크 가상화를 위한 대표적인 개방적 아키텍처로 OpenFow를 들 수 있다. OpenfFow는 가상 네트워크(Software Defined Network) 개념을 실현하기 위한 랜 스위치 제어 프로토콜의 집합체로서 데이터 센터 등 주로 유선랜 환경을 목표로 설계되어 활용되고 있다. 이 논문에서는 OpenFlow를 무선랜의 AP(Access Point)에 적용하여 WiFi 디바이스들로 구성된 가상 무선 네트워크 관리 프레임을 구현한다. 구현된 관리 프레임은 WiFi 디바이스들의 토폴로지와 트래픽 상황을 중앙 관제 센터에서 모니터링할 수 있고, 플로우 경로를 설정함으로써 라우터를 경유하지 않고 AP 수준에서 스위칭(라우팅)이 가능하여 전체적인 트래픽 혼잡을 크게 줄일 수 있다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.7
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• pp.118-127
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• 2010

Current TCP/IP-based Internet architecture has been used for over 30 years, however it will confront with fundamental problems due to new protocol extension limitation since communication environments will change drastically and various user requirements will be emerging in near future. To solve these problems, major countries have started Future Internet researches based on clean slate approach and they will deploy large-scale testbed to experiment and verify new functions. OpenFlow switch technology has been proposed as a new experimental technology for independent protocol that can utilized the legacy network devices and does not interfere with the production Internet traffic. Korea also started Future Internet testbed project called FIRST and OpenFlow switch with NetFPGA card will be used to deploy this testbed. To interconnect distributed testbed using OpenFlow switches, logical tunnel should be established by encapsulating MAC frame inside a unicast IP packet between OpenFlow switches because OpenFlow switches are not directly connected. In this paper, we have implemented a NetFPGA-based that performs MAC in IP tunneling between various OpenFlow switch sites implemented in domestic research network KOREN. The performance evaluation shows that the NetFPGA-based capsulator reveals better performance than the software-based tunneling and it can be utilized as a testbed for experimentation of Future Internet technologies.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.418-420
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• 2012

정보화 사회로 발전하고 네트워크가 큰 폭으로 발전함에 따라 사회에 대한 네트워크의 의존도가 커져 가고 있다. 그러나 네트워크가 발전할수록 미래의 다양한 사용자 요구사항 및 새로운 네트워크의 한계성이 나타나고 있다. 이러한 문제를 해결하기 위한 방안 중 하나로 OpenFlow기법이 제안되었다. 본 논문에서는 이러한 OpenFlow기반의 네트워크를 관리하기 위해 VN Manager(Virtual Network Manager)와 이를 활용한 경로 관리 프로그램을 구현하였다. 또한 경로 생성시 QoS를 보장하기 위해 Admission Control이 가능하도록 하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.590-593
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• 2012

현재 인터넷은 하드웨어 종속적인 특징을 가지고 있어 급변하는 환경에 적응하기 힘들다. 이러한 제약사항은 관련 산업 발전을 더디게 하고 있다. 이와 같은 네트워크 환경에서 산업 발전을 위하여 네트워크 인프라에 유연성을 제공할 수 있는 기술의 개발이 필요하다. 그러한 문제를 해결하기 위해 오픈프로토콜인 OpenFlow의 Programmable Network의 특성을 이용하여 네트워크 가상화를 구현하였으며, 응용 서비스별 Virtual Network를 제공하는 방안에 대해 연구하였다. 이를 위하여 OpenFlow 기반의 Programmable Network를 구축하였으며, 동적으로 구성이 가능한 네트워크에서 가상화를 제공하기 위해 VNAPI를 개발하였다. 또한, VNAPI를 통하여 신뢰성 있고 효율적인 응용 서비스의 전달을 위하여 Virtual Network Topology에 대한 설계를 같이 수행하였다.

• The Journal of the Korea Contents Association
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• v.12 no.12
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• pp.46-53
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• 2012

The traffic in research network for the new structure of the network and new service research has the various properties. From the perspective of a specific traffic point of view, transmission of traffic with different requirements using a single routing protocol is an obstacle to satisfy requirements. In this study, we classify the properties of the traffic into two types. We propose the way that we can get the overall optimization effect, the experiment proves it by providing independent multiple forwarding path by applying optimized algorithm by types. In order to distinguish each type of traffic we use the ports on the switch and in order to implement independent path we apply OpenFlow system. In other words, we present the measure that can be implemented to improve the satisfaction of the traffic by making multiple paths by OpenFlow controller according to the type of traffic and by enforcing in Forwarder.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.1
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• pp.34-45
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• 2013

Recently, world-wide research activities on new network architectures and protocols are being actively progressed. Furthermore, research activities on testbed and related technologies for supporting those activities are being actively performed. In domestic study, research on the OpenFlow protocol based future Internet testbed implementation and research on its virtualization for supporting independent research experiments are being performed at the same time. The network virtualization is a technology which maximizes the testbed utilization without interfering each other for the individual research when many researchers share the testbed. In this paper, we implemented a Enhanced FlowVisor by extending basic FlowVisor by adding QoS functions which are admission control and minimum bandwidth guarantee. On the testbed, we performed a real-time video streaming experiment for verifying the performance of the Enhnaced FlowVisor on the OpenFlow protocol based future internet testbed. The result shows that the Enhanced FlowVisor can provide reliable and stable QoS to the individual researches without disturbing each other traffic on virtualized networks of the future Internet testbed.

• KIISE Transactions on Computing Practices
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• v.21 no.1
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• pp.1-12
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• 2015

To realize futuristic services with agility, the role of the experimental facility (i.e., testbed) based on integrated resources has become important, so that developers can flexibly utilize the dynamic provisioning power of software-defined networking and cloud computing. Following this trend, an OpenFlow-based SDN testbed environment, denoted as OF@TEIN, connects multiple sites with unique SmartX Racks (i.e., virtualization-enabled converged resources). In this paper, in order to automate the multi-point L2 (i.e., Ethernet) inter-connection of OpenFlow islands, we introduce an automated tool to configure the required Network Virtualization using Generic Routing Encapsulation (NVGRE) tunneling. With the proposed automation tool, the operators can efficiently and quickly manage network inter-connections among multiple OpenFlow sites, while letting developers to control their own traffic flows for service realization experiments.

• The KIPS Transactions:PartC
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• v.18C no.6
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• pp.423-432
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• 2011

Recently, OpenFlow has been paid attention to as a fundamental technology which provides a function of virtualization and programmability in network. In Korea, deployment of OpenFlow networks in campuses and the interconnection between them through tunneling in layer 3 has been performed. However, the performance of the interconnected networks is decreased due to delay in IP layer. In this paper, we design and deploy nation-wide, not local, OpenFlow networks in a pure layer 2 environment over KREONET. After that, we do end-to-end Round-trip Time measurements and TCP/UDP performance tests in OpenFlow and normal networks, and do comparison and analysis on the test results. The results show that the nation-wide OpenFlow networks provide equal performance to normal networks except for the initial packet loss for UDP streaming. In regards to the performance decrease due to early UDP packet loss, we can mitigate it by implementing exceptional procedures in a controller which deal with the same continuous "Packet_in" events.