• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.6
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• pp.77-87
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• 2007

It will need a quite long time to replace IPv4 protocol, which currently used, with IPv6 protocol completely, thus we will use both IPv4 and IPv6 together in the Internet during the period. For coexisting protocols, IETF standardized various IPv4/IPv6 transition mechanisms. However, new security problems of IPsec adaptation and IPv6 packet filtering can be raised by tunneling mechanism which mainly used in transition mechanisms. To resolve these problems, we suggested two improved schemes for packet filtering functions, which consists of an inner header filtering scheme and a dedicated filtering scheme for IPv4/IPv6 transition mechanisms. Also we implemented our proposed schemes based on Linux Netfilter framework, and we tested their filtering functions and evaluated experimental performance of our implementation on IPv4/IPv6 transition testbed. These evaluation tests indicated that our improved packet filtering functions can solve packet filtering problems of IPv4/IPv6 transition mechanisms without severely affecting system performance.

• Journal of Information Processing Systems
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• v.4 no.3
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• pp.87-96
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• 2008

This paper analyzes the handover latency of Mobile IP and mobile SCTP over IPv6 networks. The analytical results are compared with the performance by experiment over Linux testbed. For analysis, we consider the two handover scenarios: horizontal handover and vertical handover. From the results, we see that mSCTP can provide smaller handover latency than Mobile IP. Moreover, mSCTP can give much smaller handover latency for vertical handover, compared to horizontal handover.

• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1601-1604
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• 2003

본 논문에서는 PDA. Hand PC(HPC)등과 같은 모바일 단말에 운영체제로써 Embedded Linux를 채택하였을 경우 고려해야 할 Hardware 사양, I/O interrupt latency에 따른 성능. 스케줄링 정책에 따른 성능에 대하여 논한다. 대상 타겟으로 사용한 HPC 의 하드웨어 사양에 설명하고, Embedded Linux와의 연동에 있어서 문제점을 살펴본다. 또한 각종 I/O device들의 Interrupt latency에 따른 성능저하와 스케줄링 정책에 의한 성능저하에 대하여 분석하고. 해결 방안에 대하여 논한다. 마지막으로 실제 예로서 Mobile IPv6 S/W Stack을 이용한 실제 검증을 수행하고 성능 향상 방안을 제시한다.

• Journal of Korea Multimedia Society
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• v.10 no.1
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• pp.74-82
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• 2007

IPv6 is the internet protocol for next generation which can solve the problem of IPv4 protocol. Mobile IPv6 efficiently provides the mobility for mobile devices holding the properties of IPv6. iSCSI(Internet Small Computer System Interface) is a block-oriented storage access protocol that enables a user to recognize a remote storage as their own local block device through general TCP/IP networks. Since iSCSI uses a standard Ethernet switch and router for this kind of access, it can not only be applized to Ethernet technologies, but can also be used to create a storage networking system without any distance restrictions that can equally be applied to a wireless network environment. Accordingly, this paper presents an alternative approach to overcome the limited storage space of mobile devices based on the IPv6 iSCSI initiator driver which was originally designed for wired networks. Also, this paper describes about the implementation and performance analysis of mobile education service system using virtual storage devices in IPv6 wireless networks.

• Journal of KIISE:Information Networking
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• v.33 no.6
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• pp.407-419
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• 2006

As substituting IPv6 network for all IPv4 network in a short time seems unattainable due to high cost and technical limitation, IPv4 and IPv6 are expected to coexist for a certain period of time. Under the co]existing environment of IPv4 and IPv6, interworking brings a number of extra security considerations even if it may have no security problem for each protocol respectively. Thus, the analysis and solutions for those various attacks toward IPv4/IPv6 interworking-related security are inevitably required for the sake of effective transition and settlement to IPv6. In this paper we carried out a proper rule of packet filtering for IPv6-in-IPv4 tunneling interworking environment to protect the IPv4/IPv6 interworking-related security attacks. Design and implementation of the packet filtering system suitable for IPv4/IPv6 tunneling environment in the form of Linux netfilter and ip6tables are also shown. Thru this study, the packet filtering system was found operating correctly ill the tunneling mechanism.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11b
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• pp.1101-1104
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• 2003

급증하는 인터넷 사용자와 함께 인터넷 트래픽도 급격히 증가함으로 인하여, 한정된 네트워크 자원에 대한 효율적인 네트워크 관리의 필요성이 중요한 이슈로 등장하고 있다. 본 논문에서는 Libpcap 라이브러리를 이용하여 패킷을 수집하는 Tcpdump를 임베디드 리눅스 시스템에 적용하여 차세대 인터넷 프로토콜인 IPv6기반에서 트래픽 모니터링을 함으로써, 효율적인 네트워크 관리를 위한 기술을 제안한다. 본 트래픽 모니터링 시스템은 임베디드 리눅스를 이용하여 IPv6 패킷을 수집 및 분석하고, 측정된 트래픽 모니터링의 정보를 바탕으로 네트워크 장비들을 효율적으로 관리 및 제어한 수 있는 트래픽 측정 모델을 설계하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.275-278
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• 2002

이동성을 제공하기 위해 IETF에서는 Mobile IP 라는 프로토콜을 제안하였다. IETF에서는 주소고갈 문제를 해결하기 위해 앞으로도 계속적인 수요를 충족시킬 만큼의 충분한 주소를 제공할 수 있는 IPv6의 차세대 인터넷 프로토콜을 채택하였다. 본 논문에서는 Mobile IP에서 핸드오프가 발생할 때 패킷의 손실을 최소화하는 과정을 알아본다. 또한 Mobile IP기능을 IPv6에서 재설계함으로써 이동 노드가 접속점을 변경시킬 때 핸드오버가 발생하는데 이때, 성능 향상을 위한 바인딩 캐쉬 서버 도입과 지역등록 방안을 제안한다. 제한 사항에 대한 시뮬레이션을 하기 위해 Linux Machine을 이용한 Network Simulator(version-2)를 사용 하였다.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.3
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• pp.47-59
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• 2007

IPv4 NAT, which often used in households or under SOHO environments, is one of the factors that delays IPv6 propagation. As IPv4 NAT does not operate properly under the transition mechanism like ISATAP or 6to4 that acts as IPv6-in-IPv4 tunneling type, Microsoft proposed Teredo in order to resolve this issue. However, tunneling transition mechanism like Teredo has a security problem. That is, being tunneled packets have dual IP headers; general firewall systems apply the filtering rules only to the outer header but not inner header when these packets pass the firewall. Furthermore, attacks using unregistered server and relay can take place in Teredo. To resolve these problems, we propose a new packet filtering mechanism exclusively for Teredo. The proposed packet filtering mechanism was designed and implemented by using Linux Netfilter and ip6tables. Through functional and experimental performance tests, this packet filtering system was found operating properly and solving the Teredo packet filtering problems without serious performance degradation.

• Journal of Communications and Networks
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• v.17 no.6
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• pp.647-655
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• 2015

Low-power and lossy networks (LLNs) comprised of thousands of embedded networking devices can be used in a variety of applications, such as smart grid automated metering infrastructures (AMIs) and wireless sensor networks. Connecting these LLNs to the Internet has even greater potential, leading to the emerging concept of the Internet of Things (IoT). With the goal of integrating LLNs into IoT, the IETF has recently standardized RPL and 6LoWPAN to allow the use of IPv6 on LLNs. Although there already exist several studies on the the performance of RPL and embedded IPv6 stack in LLN, performance measurement and characterization of TCP over RPL in multihop LLNs is yet to be studied. In this article, we present a comprehensive experimental study on the performance of TCP over RPL in an embedded IPv6-based LLN running over a 30-node multihop IEEE 802.15.4 testbed network. Our results and findings are aimed at investigating how embedded TCP interoperates with common Linux TCP and underlying RPL (and vice versa), which furthers our understanding of the performance trade-offs when choosing TCP over RPL in IPv6-based LLNs.

• The KIPS Transactions:PartC
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• v.12C no.4 s.100
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• pp.551-558
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• 2005

In this paper, we implement the fast handovers for mobile IPv6 (FMIPv6) on Linux system. Due to its dependency on operations in layer-2 (L2), we have added some functions into the network driver to generate triggers as the mobile node moves. We design and implement the FMIPv6 functions divided into two parts as an access router and a mobile node. We compare the packet loss and delay of the FMIPv6 implementation during the handover period with those of the MIPv6 and investigate the performance improvement.