• The Transactions of the Korea Information Processing Society
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• v.2 no.3
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• pp.406-416
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• 1995

This paper is concerned with a routing protocol for cost-effective communications between mobile hosts on computer networks in which mobile hosts can move freely their physical positions. The proposed routing protocol consists of two protocols : one is called location registration protocol performing registration of the location information as the mobile host does move; the other one is called message transfer protocol which actually delivers a message to the destination mobile host. The detailed protocol's operational behavior and major characteristics are presented. And it is shown that our protocols are superior to previous ones, in terms of the communication cost(i.e, number of messages) required for routing a message, and are functionally improved ones.

• The KIPS Transactions:PartB
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• v.9B no.5
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• pp.517-522
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• 2002

Mobile agent systems offer a new paradigm for distributed computation and a one of solution for limitation of existent Client-server model. Mobile agent systems provide interface that can migrate from host to host in a heterogenous network. For secure execution, it must solve security problem of mobile code before. In this paper, we are propose the protocol that applied signature technique and hash chain technique. This protocol enable one to offer forward integrity, non-repudiation, and forgery detection, when mobile agents are perform the task by migrating a network.

• The KIPS Transactions:PartC
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• v.13C no.5 s.108
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• pp.635-640
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• 2006

The Snoop in the BS (Base Station) performs a local retransmission over wired-wireless networks to recover packet loss quickly. However, when the MH (Mobile Host) leaves the reception range of the signal, the local retransmission causes performance to degrade. In this paper, we minimize the packet loss and local retransmission caused by the unreachability from BS to MH to improve network performance. To do this, we suggest to add RSS(Received Signal Strengths) flag bit in ACK packet of MH. By using this flag bit, the BS decides whether it retransmits or not to minimize packet loss. The result of the simulation by ns-2 shows a big improvement of performance in the networks.

• The KIPS Transactions:PartA
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• v.11A no.6
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• pp.413-418
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• 2004

According as computer hardware became smaller and its performing power became improved due to the developed computer technology, clients demand more powerful accessibility to various information through getting the information at every time and every place. These needs led to the Ubiquitous computing technology which makes it possible to have access to a specific information regardless of clients' physical location. In this paper, we propose an approach that mobile host can get data from proper contents server by applying Contents Distributing Network to wireless network. By simulation, this paper proves that this approach can Improve performance by using contents server selection in wireless network. This research will contribute to realizing the Ubiquitous computing technology.

• The Transactions of the Korea Information Processing Society
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• v.7 no.11S
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• pp.3675-3683
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• 2000

The Handoff is the core technical factor that is required when mobile host moves from one area to another, while transmitting and receiving data. The existing works try to minimize the loss of pockets by forwarding packets to the Cell which a mobile host will move to. However, though the loss quantity is little, the accumulated loss can del(rade the performance of the TCP, and can be a serious problem if data is sensitive to the loss of packets. In this paper, we can reduce a memory requesting in FA by restricting the mobile host to move within at most 2 movable cells and design the improved handoff protocol for Mil to receive packets seamlessly in spite of handoff. We can evaluate that the suggested method is superior to the previous method, as a result of comparing with it.

• The KIPS Transactions:PartC
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• v.18C no.6
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• pp.405-412
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• 2011

Our proposed mobility management scheme is based on Multicasting and HIP(Host Identity Protocol) in PMIPv6(Proxy Mobile IPv6) Networks, and allows users to handoff within and across different administrative domains. The main advantage of our scheme is to enable the inter-domain handoff of both types of nodes with a reduced signalling overhead and packet losses. Specifically, the scheme enables the interworking between host-based and network-based mobility support, by means of the interaction between PMIPv6 with Multicasting and HIP. Performance evaluations demonstrate that our scheme improves the handoff latency and packet losses compared to other global mobility management protocols.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.414-418
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• 2003

VoIP is a core technology used to transmit both voice and data in an integrated packet' form. Within this technology, SIP is the signaling protocol used for 'real time' call services; particularly those where H323 is used. Yet, when considering the needs of mobile users, it is essential we integrate VoIp within the mobile technology so the mobile host is able to receive the 'packet' transported and by, and connected to, any available internet-address. For all this to occur, we need to improve Network Delay by reducing transmission problems associated with mobile services. If we are to obtain an optimal service then we must reduce any network delays which may arise from joining Mobile IP and VoIp services. This paper, therefore, considers how, unlike previous research, these delays may be improved through the use of the signaling technology\ulcorner SIP. It also considers how this research may be introduced into current wired and wireless integrated services enabling them to use the IP 'packet'.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.4C
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• pp.433-441
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• 2003

We propose a new resource reservation scheme called MC-HMRSVP(Mobile clustering based-Hierarchical mobile ReSource reserVation Protcol) that is an extension of HMRSVP[3,4]. MC-HMRSVP always establishes a virtual cluster called Mobile Cluster, which includes its immediately adjacent MA(Mobile Agent) for passive reservation as well as the current MA for active reservation to which MH(Mobile Host) belongs. Our scheme also establishes the MC regardless of intra/inter region movement by GMA(Gateway Mobile Agent) function when a MH moves. To provide a general formulation on analyzing the performance in terms of reservation cost, we also model the resource reservation cost by using a simple recursive equation. Then, we show that our scheme decreases the reservation cost in comparison with the existing HMRSVP extentions.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.2
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• pp.75-82
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• 2008

Mobile IP was proposed to overcome identity problem of original IP address system caused by mobility of wireless mobile host. To complete its network handoff procedure, it must receive a mobile advertisement broadcasted by mobile agent. Generally, in a mobile IP system, mean time delay, 500ms, in a network handoff procedure is a critical problem of wireless service such as Voip, multimedia streaming. A caching agent caches a latest mobile advertisement, and replays it by receiving solicitation message from a mobile node finishing link layer detection. But, during the procedure of mobile registration, many packets from service provider to the mobile host would be lost and handoff time delay would be increased. In this thesis, we propose an unproved caching agent technique which can forward data packets while handoff procedure, and CoA pool for fast mobile IP registration.

• 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.