• Journal of KIISE:Information Networking
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• v.29 no.3
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• pp.242-252
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• 2002

When a Mobile IP handoff occurs, the packets in flight can be lost because they are tunneled based on out-of-date location information. In this parer, we propose an enhanced handoff protocol that achieves no packet loss during Mobile IP handoff over a wireless LAN. Our handoff protocol predicts the next foreign agent that a mobile host is to visit by using: the information from the data link layer of wireless LAN. After that, when a Mobile IP handoff occult, the current foreign agent forwards the packets destined to a mobile host to the predicted foreign agent which buffers them. This eliminates packet loss and reduces the packet forwarding delay. Our handoff protocol is simulated using the Network Simulator-2 (ns-2) and shows the substantial performance enhancement of TCP with much less overhead up to 6.2 times compared to standard Mobile IP.

• Journal of the Institute of Convergence Signal Processing
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• v.9 no.3
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• pp.230-237
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• 2008

Recently, lots of interest and competition in developments related to the autonomous-vehicle robot are being further increased. However, the absence of the standard architectures for effectively controlling the autonomous-vehicle robot led to many difficulties such as the long duration of development and the uncompatibility with other autonomous-vehicle robots. Accordingly, we implemented a mobile autonomous-vehicle robot system based on JAUS standard architecture. The mobile robot communicates with the remote-control system by using wireless LAN UDP/IP JAUS command massages. Its effectiveness is showed through the experimental results related to the navigation of implemented robot.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.10
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• pp.126-134
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• 2006

This paper describes the development of an embedded wireless LAN controller which can be in parallel operated with an existing utility controller. The embedded controller mainly consists of Prism(R) 2.5 chip set and Atmega 128 microcontroller. In order to communicate over the network, the controller including TCP/IP stack (IP, TCP, UDP, and ICMP), telnet, and X/Z modem has been developed. For a specific application, we have proposed an special method to convert data structure between TCP/IP and X/Z modem and a data buffer algorithm to minimize the RAM memory usage. Finally, the correctness and performance of the protocols are tested and verified using $CommView^{(R)}\;and\;DU^{(R)}$. The development is satisfactorily operated only for 3,381 bytes of RAM usage without sacrificing interoperability between hosts.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1086-1089
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• 2009

UPnP(Universal Plug and Play) 홈네트워크에서 무선랜은 위치에 상관없이 쉽게 설치하여 사용할 수 있어 사용자에게 편의성을 제공 하지만, AP(Access Point)는 해킹을 통한 MAC 주소 및 SSID(Service Set Identifier), WEP(Wired Equivalent Privacy)의 암호를 쉽게 알 수 있어 보안에 취약하다. 또한 UPnP 는 TCP/IP 를 사용하는 인터넷 표준과 기술을 기반으로 하고 있고 HTTP, UDP, SSDP, GENA 등의 표준 프로토콜을 사용하기에 보안 대책에 취약점을 가지고 있다. 본 논문에서는 댁외에서 UPnP 홈네트워크에 사용되는 AP 를 해킹하고, 해킹한 AP 정보를 이용하여 UPnP 홈네트워크의 디바이스 정보를 취득하고, 댁내 컨트롤 포인트(Control Point)를 해킹하여 MAC 주소 및 IP 주소를 댁외 컨트롤 포인터로 변조하여 UPnP 홈네트워크 디바이스를 제어하는 실험으로 UPnP 홈네트워크 보안의 취약점에 대해 분석한다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.126-128
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• 2000

본 논문은 무선 랜 환경에서 Mobile IP를 기반으로 하는 이동 호스트가 핸드오프를 수행할 때 발생될 수 있는 패킷 손실 제거하고, 멀티미디어 데이터의 특성을 고려한 핸드오프 프로토콜을 제안한다. 제안된 핸드오프 프로토콜은 Mobile IP의 확장으로 무선 랜 기술을 이용하며, 현재 FA(Foreign Agent)가 아닌 이동 호스트가 방문할 FA에 패킷을 버퍼링함으로써 패킷 손실을 제거하고, 버퍼링된 패킷의 포워딩 시간을 최소로 한다. 제안된 핸드오프 프로토콜은 ns-2(network)에서 시뮬레이션 되었고, 멀티미디어 데이터 통신에 사용되는 UDP의 성능이 향상됨을 보여주었다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.55-60
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• 2016

In the traditional wireless LAN model, scan procedure to search a new AP starts when the predefined number of Rx failure of beacon frames are occurred. In this case, lots of data packet loss occur during MN's handover because loss of the relatively longer data packet starts before the small-sized beacon loss. Newly developed scanning mechanism in this paper has the beacon counter that increases when the Rx power level of beacon frame is less than the threshold and the previous rx power level. New scan procedure starts when the counter exceeds the predefined number. Beacon Rx power threshold is verified and performance of the new WLAN model is evaluated under UDP and TCP traffic environment.