• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.838-839
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• 2016

IEEE 802.15.4 is the standard wireless link technology for low power, low cost, but long lifetime applications including wireless sensor network (WSN). Currently, whether or not IP architecture should be used in WSN over its 802.15.4 link is under dispute. Such kind of arguments may last for a long time without some convincing experimental measurements of real case performances of IP over 802.15.4 implementation, and thus prevent the advance of related research. In RFC4944, IETF proposed the 6LoWPAN specification to enable IPv6 communication over low power, wireless personal area networks. We try to alleviate the dispute and make the direction clearer to the community so as to promote further valuable research in this topic.

• Journal of Information Processing Systems
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• v.5 no.3
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• pp.117-130
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• 2009

By providing ubiquitous Internet connectivity, wireless networks offer more convenient ways for users to surf the Internet. However, wireless networks encounter more technological challenges than wired networks, such as bandwidth, security problems, and handoff latency. Thus, this paper proposes new technologies to solve these problems. First, a Security Access Gateway (SAG) is proposed to solve the security issue. Originally, mobile terminals were unable to process high security calculations because of their low calculating power. SAG not only offers high calculating power to encrypt the encryption demand of SAG's domain, but also helps mobile terminals to establish a multiple safety tunnel to maintain a secure domain. Second, Robust Header Compression (RoHC) technology is adopted to increase the utilization of bandwidth. Instead of Access Point (AP), Access Gateway (AG) is used to deal with the packet header compression and de-compression from the wireless end. AG's high calculating power is able to reduce the load on AP. In the original architecture, AP has to deal with a large number of demands by header compression/de-compression from mobile terminals. Eventually, wireless networks must offer users "Mobility" and "Roaming". For wireless networks to achieve "Mobility" and "Roaming," we can use Mobile IPv6 (MIPv6) technology. Nevertheless, such technology might cause latency. Furthermore, how the security tunnel and header compression established before the handoff can be used by mobile terminals handoff will be another great challenge. Thus, this paper proposes to solve the problem by using Early Binding Updates (EBU) and Security Access Gateway (SAG) to offer a complete mechanism with low latency, low handoff mechanism calculation, and high security.

• 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 Communications and Networks
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• v.14 no.1
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• pp.91-103
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• 2012

Network mobility (NEMO) based on mobile IP version 6 has been proposed for networks that move as a whole. Route optimization is one of the most important topics in the field of NEMO. The current NEMO basic support protocol defines only the basic working mode for NEMO, and the route optimization problem is not mentioned. Some optimization schemes have been proposed in recent years, but they have limitations. A new NEMO route optimization scheme-involving a combination of the optimized route cache protocol (ORC) and reverse routing header (RRH) and the use of a quota mechanism for optimized sessions (OwR)-is proposed. This scheme focuses on balanced performance in different aspects. It combines the ORC and RRH schemes, and some improvements are made in the session selection mechanism to avoid blindness during route optimization. Simulation results for OwR show great similarity with those for ORC and RRH. Generally speaking, the OwR's performance is at least as good as that of the RRH, and besides, the OwR scheme is capable of setting up optimal routing for a certain number of sessions, so the performance can be improved and the cost of optimal routing in nested NEMO can be decreased.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.5
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• pp.105-111
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• 2008

Mobility support for mobile networks will be important to minimize the packet overhead, to optimize routing, to reduce handoff latency, and to reduce the volume of handoff signals. Mobile IPv6 (MIPv6) and Hierarchical MIPv6 (HMIPv6) are one of mobility management protocols (MMPs) that provides network layer mobility over all access technologies. However, the communication quality of these candidates is severely degraded during handoffs. As another way to improve the handoff performance of a mobile network by conventional MMPs such as MIPv6 and HMIPv6, we propose a Low Latency Handoff Scheme (LLHS) combining Fast MIPv6 (FMIPv6) with HMIPv6 extension with buffering function, in which Mobility Anchor Points (MAPs) buffer packets destined to the Mobile Routers (MRs) or MNs within a mobile network during handoffs. The simulation results show that the proposed scheme reduces transmission delay and packet loss in UDP communication.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.1
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• pp.55-59
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• 2010

Currently in a Ubiquitous Sensor Network (USN) research field, supporting mobility is recognized as an important technology. MIPv6 and Network Mobility(NEMO) Basic Support Protocol are standard protocols to support mobility in the Internet. However, if they are applied to USN with no modification, handoff performance decreases due to the size of their binding message. An existing lightweight protocol for NEMO protocol has a compatibility problem of Sequence Num. and does not optimally compress binding messages considering 6LoWPAN network structure and addressing. This paper proposes optimal header compression which supports node-based mobility and network-based mobility. Our optimal compression technique compresses a 32bytes binding update(BU) message and a 12bytes binding ACK(BA) message of MIPv6 into 13bytes and 3bytes, and a 40bytes BU message and a 12bytes BA message of NEMO protocol into 13bytes and 3bytes. The result shows that our protocol compresses 15bytes (NEMO-BU) and 1byte (NEMO-BA) more than the existing protocol and achieves 8.72% handoff performance improvement.

• Electronics and Telecommunications Trends
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• v.18 no.5 s.83
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• pp.11-18
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• 2003

IETF NEMO 워킹그룹에서는 IPv6 이동 네트워크에서의 이동성 지원을 위한 여러 가지 방법들이 제안되었다. 특히, 최근 결성된 디자인 팀에서는 기존에 제안된 여러 방법들을 접목하여 NEMO Basic Support 프로토콜을 제안하였고, 워킹 드래프트로 채택되었다. 본 고에서는 기존에 제안되었던 여러 가지 망 이동성 지원 방법들을 분석하고, 현 표준화 동향에 대해서 기술한다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.527-529
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• 2003

차세대 무선네트워크에서의 인터넷 데이터 서비스는 중요한 위치를 차지할 것이다 그러한 이동 인터넷 서비스를 하기 위해서는 호스트의 이동성지원이 이루어져야만 한다. Mobile IP와 Mobile IPv6는 이러한 문제를 해결할 수 있는 기본적인 방안인데, 보다 효율적인 이동성 지원을 위하여 멀티캐스트 기반 방안들이 제안되어 왔다. 본 논문에서는 멀티캐스트에 기반한 방안들의 성능을 데이터 전달과 대역폭 사용 효율성을 통하여 장단점을 분석해 본다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7B
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• pp.760-770
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• 2011

The existing mobility management schemes do not fully support the next generation network, which is composed of IP-based core network and various access networks. Currently, ETRI has been developing the AIMS (Access Independent Mobility Service) system which satisfies the ITU-T requirements of mobility management in the next generation network. The AIMS system is designed to provide a mobile host with a fast and reliable mobility service among heterogeneous access networks. Recently, many user devices have multiple communication interfaces, e.g., 3G and WLAN, and thus they can make two or more network connections at the same time. In this paper, we design a scheme of flow mobility, i.e., the movement of selected data flows from one access technology to another, to be applied in the AIMS system, and verify the proposed scheme through the NS-3 simulation study. From the simulation results, we can know that the proposed flow mobility scheme can utilize the network resource efficiently in the heterogeneous mobile networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.8
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• pp.674-680
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• 2014

In this paper, as one of the fusion of IT and ocean technology, we propose a scheme to support NEMO in a harbor area network to provide network mobility for passengers, distribution as well as give a connection to an MN from an outside network. In a harbor area under PMIPv6 with NEMO support, a problem could be occurred due to overlapping HA/LMA tunnels and duplicate BCE fields. To Solve these problems, we consider the existing mobility option and add an optional field in the PBU message, which can notify the LMA and HA for either an initial connection or handover request. This procedure can reduce some overlapped steps of binding procedure. Hence, our proposed scheme could reduce an amount of delay and save the processing resource in the harbor area under PMIPv6 with NEMO support.