• The KIPS Transactions:PartC
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• v.13C no.1 s.104
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• pp.121-128
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• 2006

In Mobile IPv6, a handover latency is an important issue. To reduce the handover latency, mipshop working group in IETF has studied the fast handover(FMIPv6) which creates and verifies a new care-of address(NCoA) in advance before a layer 2 handover resulting in reduced handover latency. Even in FMIPv6, the NCoA must be registered in a home agent(HA). This registration still creates a significant amount of delay. To reduce registration latency, we propose a tentative and early binding update(TEBU) scheme that the NCoA is registered in the HA in advance during the layer 2 handover based on FMIPv6. We use cost analysis for the performance evaluation. As a result, we found that the TEBU scheme guarantees lower handover latency than FMIPv6 as much as approximately 21%.

• Electronics and Telecommunications Trends
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• v.22 no.6
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• pp.40-50
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• 2007

본 고에서는 이기종 네트워크 환경에서의 심리스 핸드오버 기술에 대한 기술 분석 및 관련 표준화 동향에 대하여 기술한다. 이기종 네트워크에서의 심리스 핸드오버 기술로 대표적인 IEEE 802.21 Working Group에서 표준화를 진행해온 Media Independent Handover 기술에 대한 참조 모델, 서비스, 프로토콜 및 이기종 네트워크간 핸드오버 절차를 중심으로 살펴본다. 최근 표준화 동향 파악을 위해서 2007년 10월 기준으로 IEEE 802.21 Working Group 및 IEEE 802.11u Task Group의 표준화 현황과 핵심 이슈를 정리하며, 그간 3GPP 표준과 연계한 MIH 기술 적용 현황 및 향후 추진시 고려할 사항에 대하여 기술한다. 또한, IEEE 802.21 Working Group 내 신규 그룹인 Multi-Radio Power Conservation Management Study Group과 Security Study Group의 진행상황에 대하여 살펴본다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.6
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• pp.229-240
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• 2012

The development of multimedia applications followed by development of high-speed networks has improved the performance of mobile devices with high transfer speed broadband. Mobile internet access has made possible seamless indoor and outdoor mobile multicast services. Multicasting services are used to support efficient group communications. However, mobile multicasting services have two constraints: tunnel convergence and handover latency. Many protocols and handover methods have been proposed to address these problems. The inter-LMA optimized handover model for multicasting services has previously been proposed for PMIPv6-based networks. The proposed model removes the tunnel convergence issue and reduces router processing costs. It also makes possible the performance of fast handover operations with adaptive transmission mechanisms. In addition, the proposed scheme exhibits low packet delivery costs and handover latency in comparison with existing schemes, and ensures fast handover when moving the inter-LMA domain

• Journal of Korea Multimedia Society
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• v.10 no.2
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• pp.226-235
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• 2007

Recently, the lETF NEMO working group on network mobility is standardizing a basic support for moving networks. We need a handover scheme for achieving the performance of transparency during the movement of mobile routers in nested mobile networks. But existing handover schemes for a mobile host are not suitable for network mobility because the packet transmission delay and traffic increase during mobile router's handover in nested mobile networks. Therefore, we propose a new seamless handover scheme using the bi-casting based on Mobile IPv6 for nested mobile networks in this paper. Compared with the handover schemes using bi-directional edge tunneling for host mobility support on simulation. And, the results show that the proposed handover scheme reduces the packet delay during a mobile router changes the point of attachment in nested mobile networks.

• Journal of Communications and Networks
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• v.15 no.2
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• pp.142-152
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• 2013

The network mobility basic support (NEMO BS) protocol has been investigated to provide Internet connectivity for a group of nodes, which is suitable for intelligent transportation systems (ITS) applications. NEMO BS often increases the traffic load and handover latency because it is designed on the basis of mobile Internet protocol version 6 (MIPv6). Therefore, schemes combining proxy MIPv6 with NEMO (P-NEMO) have emerged to solve these problems. However, these schemes still suffer from packet loss and long handover latency during handover. Fast P-NEMO (FP-NEMO) has emerged to prevent these problems. Although the FP-NEMO accelerates handover, it can cause a serious tunneling burden between the mobile access gateways (MAGs) during handover. This problem becomes more critical as the traffic between the MAGs increases. Therefore, we propose a scheme for designing an improved FP-NEMO (IFP-NEMO) to eliminate the tunneling burden by registering a new address in advance. When the registration is completed before the layer 2 handover, the packets are forwarded to the new MAG directly and thereby the IFP-NEMO avoids the use of the tunnel between the MAGs during handover. For the evaluation of the performance of the IFP-NEMO compared with the FP-NEMO, we develop an analytical framework for fast handovers on the basis of P-NEMO. Finally, we demonstrate that the IFP-NEMO outperforms the FP-NEMO through numerical results.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2006.06a
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• pp.318-321
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• 2006

현재 국내 국책사업으로 추진 중인 와이브로(WiBro) 기술 규격이 포함되어 있는 휴대인터넷 표준 규격인 IEEE 802.16e는 IP기반으로, 이동성이 뛰어나고 고속전송 기능의 특징을 가지고 있다. 또한 기지국간의 핸드오버(Handover)를 지원함으로써 이동성을 지원한다. 그러나 이러한 핸드오버 기법에 있어서 Replay 공격, Man-in-the-Middle 공격, Stolen-Verifier 공격 등에 취약한 문제점이 드러나고 있다. 본 논문은 이러한 기존 핸드오버 기법의 취약점을 개선하기 위해서 사용자의 인증서와 Timestamp값을 통한 IEEE 802.16e/와이브로 망에서 안전한 핸드오버 적용 방안에 대해 제안한다.

• Journal of KIISE:Information Networking
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• v.35 no.6
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• pp.538-548
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• 2008

In the Internet Engineering Task Force(IETF), Next Step in Signaling(NSIS) working group, proposed a mechanism to discover the Crossover Node(CRN), when the route is changed by Mobile Node(MN) handover. The CRN is divergence or convergence node on old and new path for reserving resources. Trough the CRN discovery mechanism, it possible to reduce a signaling delay and avoid the redundant reservation on the common path between old and new path. However, the QoS(Quality of Service) can be guaranteed continuously while the MN is performing handover, it is needed to pre-reserve the resource on the new path before completion of the handover. When the nodes on the new path try to make a pre-resource reservation before the handover, it is difficult to pre-reserve the resource with the existing CRN discovery mechanism. Therefore, we proposed a Passive CRN(PCRN) discovery scheme and pre-resource reservation mechanism. The PCRN which means an initial common point between the current reserved and the new paths, where the handover can take place.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.4
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• pp.44-51
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• 2000

Wireless ATM is the next-generation technology which can provide broadband services for mobile multimedia terminals. Proposed in this paper is a method of enabling fast handover by forming one cell group with the cell having the mobile terminal (MT) at present and six adjacent cells and storing information on COS which is to perform re-routing between new cell to which MT is moved when handover occurs and adjacent cells to which the MT can be handed over in new cells in advance. And the order of data cells is guaranteed by using the in-band marking cell during handover. Also the handover delay is analyzed and compared to the conventional handover method without COS reservation.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.505-509
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• 2007

Proxy Mobile IPv6 (PMIPv6)는 Mobile Node (MN)가 스스로 이동성을 지원하지 않더라도 Mobile Access Gate가 MN대신 이동성을 처리하여 IPv6 이동성을 지원하는 기술이다. 좀 더 향상된 핸드오버 성능을 얻기 위해 Proxy Mobile IPv6에서도 버퍼링을 통한 패킷 손실을 줄이는 기법을 사용할 수 있다. 하지만, IEEE 802.11 네트워크에서는 Handover 발생 직전에 MN이 어떠한 통보도 AP로 하지 않기 때문에 Handover시에 패킷 손실을 줄이기 위한 패킷 버퍼링 방법을 사용하기가 어렵다. 본 논문에서 PMIPv6에서 MAG와 AP가 MN의 이동성을 감지하여 버퍼링을 시작하고 Handover가 발생하였을 경우에 대비해 버퍼링을 하는 Cross-layer 버퍼링 방법을 제안한다. 이를 통해 PMIPv6에서도 MN의 변경 없이 Handover시에 발생하는 패킷 손실을 최소화 할 수 있다. 또한 간단한 성능 비교를 통하여 제안 방법이 기존 PMIPv6보다 우수함을 알 수 있다.

• Journal of KIISE:Information Networking
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• v.35 no.1
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• pp.46-55
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• 2008

As a mobility support for IP have studied, Internet Engineering Task Force(IETF) standardized the Mobile IPv6(MIPv6) protocol. When a mobile node moves between subnets, MIPv6 maintains connectivity to network and supports seamless communication, and these processes are called a Handover. Whenever the mobile node moves between subnets, the Handover is performed. The mobile node can not communicate during the Handover. This period is Galled Handover latency. To reduce this latency, mipshop working group standardizes Fast Handovers for Mobile IPv6(FMIPv6), but latency which the mobile node registers its new care-of address to a home agent and a correspondent node is still long. To solve this problem, we propose a scheme that the mobile node registers the new care-of address to the home agent and initiates Return Routability procedure in advance during layer 2 handover, based on FMIPv6 and IEEE 802.11. We analyze MIPv6, FMIPv6 and the proposed scheme in term of packet transmission cost during the Handover. Compared to MIPv6 the proposed scheme gains 79% improvement, while it gains 31% improvement compared to FMIPv6.