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

• Proceedings of the Korean Information Science Society Conference
• /
• 2002.04a
• /
• pp.568-570
• /
• 2002

최근에 IETF Mobile IP WG과 SeaMoby WG에서 2계층 트리거를 이용한 빠른 핸드오프 기법을 공통적으로 논의하고 있으나, 아직 이들 WG에서는 제출된 기고서에 대한 표준을 정의하지 않고 있다. 따라서 본 논문에서는 2계층 트리거를 이용한 빠른 핸드오프를 기존의 Mobile IP와 지역적 등록 기법에 적용하여 성능을 검증한다. 이를 위하여 OPNET을 이용한 시뮬레이션을 통해 핸드오프 등록 지연 및 수율의 성능을 평가한다. 그 결과에서 빠른 핸드오프를 적용할 경우 두 기법 모두 에이전트 메시지의 방송 주기에 무관하게 성능을 향상됨을 확인할 수 있다.

• The KIPS Transactions:PartC
• /
• v.14C no.3 s.113
• /
• pp.305-312
• /
• 2007

In this paper, we present a received signal strength (RSS) prediction model to timely Initiate link layer triggers for fast handoff in a wireless LAN system. Noting that the distance between a mobile terminal and an access point is not changed abruptly in a short time interval, an adaptive RSS predictor based on a stationary time series model is proposed. RSS data obtained from ns-2 simulations are used to identity the time series model and verify the predictability of the RSS data. The results suggest that an autoregressive process of order 1 (AR(1)) can be used to represent the measured RSSs in a short time interval and predict at least 1-step ahead RSS with a high confidence level.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2001.10b
• /
• pp.1525-1528
• /
• 2001

본 논문은 트리거 기법을 사용하여 이동 환경에서 멀티캐스트를 효율적으로 지원할 수 있는 방안을 제시한다. 제안된 기법에 의해 이동 노드는 2 계층 트리거를 이용하여 핸드오프를 미리 예측할 수 있으며, 실질적인 이동 전에 외부 에이전트에 등록하게 되어 핸드오프 후 지연 없이 멀티캐스트 서비스를 받을 수 있다. 또한, 바이캐스팅과 버퍼링을 사용하여 핸드오프 중 손실된 패킷은 즉시 재전송 받을 수 있다. 이와 같은 방안에 의해, 이동 노드는 항상 최적의 라우팅 경로를 이용하여 멀티캐스트 서비스를 받을 수 있으며, 핸드오프로 인한 멀티캐스트 패킷의 손실은 최소화 될 수 있다.

• Journal of KIISE:Information Networking
• /
• v.31 no.2
• /
• pp.158-170
• /
• 2004

Mobile IP is a base protocol to support host mobility in IP-based wireless network. It is well known that the protocol contains two main delay factors on a handoff process; one is to detect a host movement, and the other is to register the host's current location to its home network. This paper examines Layer 2(L2) handoff procedure in the IEEE 802.11 Wireless LAN, and identifies these L2 triggers that can be usefully applied to Layer 3(L3) handoff. Then, the MCAA(Multiple-Casting using Anchor Agent) mechanism is proposed. It makes use of the L2 trigger and the network topology to construct an anchor agent dynamically, and the multiple-casting scheme to prevent an ongoing packet to be lost. Using a network simulator, the proposed mechanism has been evaluated the handoff delay and the packet lost point of view, in comparison with the regional registration protocol which is the most well known micro mobility support mechanism.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.6A
• /
• pp.651-659
• /
• 2004

The Fast Handover protocol ［1］ provides seameless handover in wireless If networks by minimizing handover latency, which uses anticipation based on layer 2 (L2) trigger information. Therefore, it incurs higher signaling costs compared with the basic Mobile U protocol. Furthermore, since the L2 trigger is based on fluctuating wireless channel states, the handover anticipation may sometimes be incorrect. In the case of incorrect anticipation, unnecessary buffer space may be used for the purpose of providing a smooth handover. Therefore, it is essentical to analyze these overhead costs, in order to evaluate and compare the performance of Fast Handover with that of the basic Mobile U protocol. In this paper, we analyzed the overhead associated with Fast Handover including the signaling cost and the packet delivery cost. We formulated these costs based on a timing diagram and compared Fast Handover with basic Mobile Ipv6 in terms of their packet loss rates and buffer requirements. Also, we studied the impact of the L2 triggering time on the total overhead cost.

• Proceedings of the Korean Information Science Society Conference
• /
• 2008.06d
• /
• pp.126-130
• /
• 2008

Mobile IP는 단말에게 이동성을 제공해 줌으로써 이동하면서도 인터넷에 접속할 수 있게 해준다. 하지만 L2 연결과 L3 연결이 순차적으로 진행되어 핸드오버시 지연과 데이터 로스의 문제가 발생한다. 이러한 핸드오버 과정에서 발생하는 지연과 데이터 로스를 줄이기 위해 L2 트리거를 이용한 Fast Handover 기술이 개발되었지만 Fast Handover 기술 역시 L2 연결과 L3 연결이 독립적으로 진행된다. 본 논문에서는 Mobile IP의 L3 핸드오버 과정과 이기종 네트워크들의 L2 핸드오버 과정을 통합하고 핸드오버 과정을 최적화하여 성능 개선된 핸드오버 방안을 제안하고 성능평가를 통해 우수함을 보인다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.4A
• /
• pp.377-386
• /
• 2008

In this paper, a new handover management scheme has been proposed to reduce handover latency and to support fast handover without packet losses, so that it may be applicable to the wireless mobile Internet system such as IPv6-based WiBro system. To minimize the handover latency in processing of movement detection, we propose the handover management scheme which simplifies the handover message exchanging procedure between mobile subscriber station (MSS) and network by integrating layer 2 and layer 3 handovers efficiently based on the layer2 information. To reduce the processing delay from new care-of-address (NCoA) configuration during handover, we propose that NCoA is created, distributed and managed by new access control router (NACR). In addition, in order to minimize the packet transmission delay and eliminate the packet losses, the proposed scheme employs a crossover router (CR) which is upper network located over PACR and NACR and employs the packet buffering for MSS. The simulation study shows that the proposed scheme achieves loss-free packet delivery and low latency in the environment of narrow overlapped cell area or high velocity of the MSS, comparing the performance with the conventional schemes.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.10B
• /
• pp.630-637
• /
• 2007

In this paper, we propose an effective handoff mechanism using events at the layer 2 and a tunnel-based mechanism that is performed by sharing information of a mobile node and anticipated-based handoff. Also, we propose a novel anticipated-reservation mechanism using the events triggered at layer 2 to make easy a resource reservation procedure. Comparing with the existing mobile IPv6 handoff mechanism, our proposed handoff mechanism can reduce an amount of handoff latency and traffic volume between access routers where handoff is performed. In the anticipated-reservation mechanism, the amount of signaling traffics between an mobile node and the correspondent nodes can be reduced and then the allocation of resource can be accomplished. We present the performance of our proposed handoff mechanism in the wireless network environment by ns-2 simulation. Although the anticipated-reservation mechanism including a proxy agent is explained without performance evaluation, we can validate the operation of our proposed model only by the procedure of message flow.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.47 no.12
• /
• pp.45-51
• /
• 2010

The main issue in mobile cloud computing is how to support a seamless service to a mobile mode. Mobile IPv6 (MIPv6) is a mobility supporting protocol which is standardized by the Internet Engineering Task Force (IETF). Mobile IPv6 fast handovers (FMIPv6) is the extension of MIPv6 which is proposed to overcome shortcomings of MIPv6. Recently, fast handovers for Mobile IPv6 over IEEE 802.16e which is one of broadband wireless access systems has been proposed by the IETF. It was designed for supporting cross-layer fast handover. In this paper, we propose an enhanced cross-layering mobile IPv6 fast handover over IEEE 802.16e networks. In our scheme, a new access router generates a new address for the mobile node by using a layer 2 trigger. We utilize a layer 2 message which is sent from a new base station to the new access router in order to inform the new access router of information of the mobile node. A previous access router sends a binding update message to the mobile node's home agent when it acquires the new address of the mobile node. We evaluate the performance of the proposed scheme compared with the existing schemes in terms of the signaling cost and the handover latency. From the results, we observe that the proposed scheme can support fast handover effectively over IEEE 802.16e networks than existing schemes.