• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.399-402
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• 2013

PMIPv6(Proxy Mobile IPv6)는 네트워크 주도형 IP 기반 이동성 관리 프로토콜로서 액세스 시스템의 종류나 단말의 능력에 의존하지 않고, 단말 이동성 제어가 가능하다. 이러한 PMIPv6에 SIP 이동성을 접목하면 더 효율적인 경로를 사용해 터미널 이동성 및 세션 이동성을 확립할 수 있다. 이러한 이동성 관리를 위해 현재 PMIPv6-SIP에 대한 활발한 연구가 진행되고 있지만, 효과적인 성능평가 및 수학적 모델링이 표준화되지 못하고 있다. 이에 새로운 PMIPv6-SIP 아키텍쳐를 제안하고 핸드오버 시에 발생되는 지연과 패킷손실을 Pure-SIP과 비교하여 수학적인 모델링을 통한 효과적인 성능평가를 제안한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.5B
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• pp.437-442
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• 2011

As an Internet Engineering Task Force (IETF) Working Group, 6LoWPAN is standardizing the IPv6 packet transfer technology in accordance with IEEE 802.15.4. It has completed two Request for Comments (RFC) documents, one of which, RFC 4944, addresses fragmentation, reassembly, and header compression technologies. In this paper, a communication mechanism is proposed to provide efficient communication between 6LoWPAN and external nodes. In this mechanism, the gateway between 6LoWPAN and external networks serves as the proxy gateway between nodes. The simulation was conducted using QualNet to compare the performance of the proposed mechanism and the existing RFC 4944 method. The comparative analysis of the proposed mechanism and the existing method showed that the proposed method performed better.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.6A
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• pp.85-96
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• 2008

Neighbor Discovery(ND) protocol is used to exchange an information of the neighboring nodes on the same link in the IPv6 protocol environment. For protecting the ND protocol, firstly utilizing Authentication Header(AH) of the IPsec protocol was proposed. But the method has some problems-uses of key exchange protocol is not available and it is hard to distribute manual keys. And then secondly the SEcure Neighbor Discovery(SEND) protocol which protects all of the ND message with digital signature was proposed. However, the digital signature technology on the basis of public key cryptography system is commonly known as requiring high cost, therefore it is expected that there is performance degradation in terms of the availability. In the paper, to improve performance of the SEND protocol, we proposed a modified CGA(Cryptographically Generated Address) which is made by additionally adding MAC(Media Access Control) address to the input of the hash function. Also, we proposed cache mechanism. We compared performance of the methods by experimentation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.1
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• pp.1-10
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• 2012

Mobility and quality of service (QoS) are becoming the more important issues in wireless communications. The traditional Internet service is expanding into new access media and applications. Since wireless communication services are accompanied by frequent handovers at remote sites, scalable and fast handover has become a prerequisite for ubiquitous communication. In this paper, the differentiated service (Diffserv) model is deployed in heterogeneous proxy mobile IPv6 (PMIPv6) networks to satisfy the QoS guaranteed service and fast handover requirements. The operational procedures for QoS guaranteed global roaming are presented. In addition, QoS management and handover cost evaluation schemes based on a mobile host's movement scope are proposed. This paper analyzes the reduction in handover delay in a network-based localized mobility management framework. We propose and analyze a PMIPv6 optimized with a global mobile access gateway (G-MAG), which is a network-based entity, to further improve the handover performance in terms of handover delay while maintaining minimal signaling overhead in the air interface among converged heterogeneous wireless networks. The handover signaling procedures with host-based MIPv6 are compared with network-based proxy MIPv6 (PMIPv6) and fast PMIPv6 assisted by G-MAG to show how much handover delay reduction can be achieved. Analytical results show that the handover delay is significantly reduced.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.9
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• pp.806-813
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• 2012

In a cloud computing environment, various solutions were introduced to provide the service to users such as Infrastructure as a Service (IaaS), Platform as a Service (PaaS), Software as a Service (SaaS) and Desktop as a Service (DaaS). Nowadays, Mobile as a Service (MaaS) to provide the mobility in a cloud environment. In other words, users must have access to data and applications even when they are moving. Thus, to support the mobility to a mobile Thin-Client is the key factor. Related works to support the mobility for mobile devices were Mobile IPv6 and Proxy Mobile IPv6 which showed performance drawbacks such as packet loss during hand-over which could be very critical when collaborating with cloud computing environment. The proposed model in this paper deploys middleware and replica servers to support the data transmission among cloud and PMIPv6 domain. It supports efficient mobility during high-speed movement as well as high-density of mobile nodes in local mobility anchor. In this paper, through performance evaluation, the proposed scheme shows the cost comparison between previous PMIPv6 and verifies its significant efficiency.

• 한국정보통신설비학회:학술대회논문집
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• 2006.08a
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• pp.134-140
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• 2006

홈 게이트웨이가 가져야 하는 기능에 대한 요구사항을 분석하고 통신사업자의 관점에서, QoS 기능과 IP 주소변환 기능을 중심으로 세부적인 스위칭 칩의 기능과 성능을 규정하였다. QoS 기능, 패킷 필터링 기능, 그리고 IPv6 주소체계 도입 등과 같이 급변하는 네트워크의 요구사항을 유연하게 수용하여, 칩의 기능과 성능을 수정하거나 추가할 수 있도록 패킷프로세서 기반으로 스위칭 칩을 설계하였으며, 홈 게이트웨이의 구성을 단순화하기 위해 스위칭 칩의 패킷 메모리와 룩업 메모리를 칩 내부에 내장하였다. 그리고 칩의 설계를 검증하기 위해 FPGA를 이용하여 6포트 스위칭 칩으로 구현하여 기능 및 성능시험을 수행하였다. NAT, Flow에 따른 패킷 분류 및 패킷 변경, SPQ, DWRR과 같은 스케줄링 등의 시험을 통하여 설계한 칩의 기능과 성능을 확인하였다.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.323-326
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• 2007

Mobility Anchor Points are used for the mobility management in HMIPv6 networks. Currently a mobile node selects the MAP farthest away from itself as a new MAP among available candidates when it undertakes a macro handoff. With this technique, however, the traffic tends to be concentrated at a MAP with the largest domain size and the communication cost increases due to the distance between the mobile node and the MAP. In this work, we proposed a cost effective MAP selection scheme. When leaving the current MAP domain. the mobile node calculates the optimum MAP domain size to minimize the local mobility cost at the new MAP domain considering mobile node's velocity and packet transmission rate. The mobile node then selects a MAP domain of size close to the optimum domain size calculated among the candidate MAP domains. In this way, it is possible for the mobile node to select an optimal MAP adaptively taking the network and node states into account, thus reducing the communication cost.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.8
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• pp.1391-1400
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• 2008

In recent yeats, SCTP is known as the next transport layer protocol for connection-oriented and reliable data transfer after TCP/UDP. The SCTP was developed on the basis of the existing TCP and was designed to eliminate defects of TCP. SCTP has the different characteristic of multi-streaming and multi-homing from TCP. In this paper, we studied the defects of the performance of communication using the traits of multi-homing. And we evaluated the efficiency for each application services on the basis of SCTP of IPv6. Also, we analysed the delay time of a packet using SCTP and TCP. We noticed that the efficiency of SCTP is better than that of TCP.

• Journal of KIISE:Information Networking
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• v.31 no.5
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• pp.429-437
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• 2004

The mobileip working group is equipped with the RR(Return Routabilit) taking the simple procedures and small amount of cryptographic operations by considering the processing capability of the mobile node however it dose not provide security features enough. To replace with enhanced methods, mobileip WG is making an effort to find the approved solutions include CGA(Craptographically Generated Address), IPsec(Internet Protocol Security) as well as the existing infrastructure such as AAA(Authentication, Authorization and Account) and PKI(Public Key Infrastructure). In this paper, we propose the authentication and route optimization based on AAA suitable for the requested security service for its successful story in wireless network such as 802.11 and 3GPP(3rd Generation Partnership Project) as well as wired one. We analyze the effectiveness of our scheme according to the traffic and mobility properties. The result shows the cost reduction up to 20 percent comparing with RR.

• Aerospace Engineering and Technology
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• v.1 no.1
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• pp.84-96
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• 2002

The major goal of this research is to use as a baseline guide for a flight model design of power system of next domestic communication satellite. For this purpose, the EPS(Electrical Power Subsystem) is designed to compliance performance requirements specified in EPS subsystem specification during all expected spacecraft operations. The regulated electrical power bus gives 42.5V to the various spacecraft loads from PCDU(Power Control & Distribution Unit) and the solar arrays are composed of 6 panel, each panel has 3 circuits including 7 string. The battery system is comprised of two batteries consisting of 26 IPV(Individual-Pressure-Vessel) NiH2 cells. Each battery can be capable of delivering 2878Watt-hours at a 80% maximum DOD(Depth of Discharge) based on the nameplate capacity of 150 amper-hours.