• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.759-761
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• 2016

ICMP(Internet Control Message Protocol) supports the processing of error in the communication network based TCP/IP. If a problem is occurred in a data transmission process, router or receiving host sends ICMP message containing the error cause to sending host. However, in this process an attacker sends a fake ICMP message to the host so that the communication between the hosts can be abnormally terminated. In this paper, we performed a study to prevent several attacks related to ICMP. To this, we have designed outbound traffic controller so that attack packet is not transmitted to network in operating system of host.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.8B
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• pp.541-548
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• 2005

IP lookup and forwarding process becomes the bottleneck of packet transmission as IP traffic increases. Previous hardware-based IP address lookup schemes using an index-based table are not memory-efficient due to sparse distribution of the routing prefixes. In this paper, we propose memory-efficient hardware based IP lookup scheme called set-associative IP address lookup scheme, which provides the same IP lookup speed with much smaller memory requirement. In the proposed scheme, an NHA entry stores the prefix and next hop together. The IP lookup procedure compares a destination IP address with eight entries in a corresponding set simultaneously and finds the longest matched prefix. The memory requirement of the proposed scheme is about $42\%$ of that of Lin's scheme. Thus, the set-associative IP address lookup scheme is a memory-efficient hardware based IP address lookup scheme.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.5
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• pp.76-87
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• 2014

Today the energy consumption of ICT networks is about 10% of the worldwide power consumption and is predicted to increase remarkably in the near future. For this reason, this paper studies energy saving strategies assuring the network-level QoS. In the strategies, the energy consumption of NIC(network interface card) on both endpoint of links decreases by selecting links and making them sleep when the total traffic volume of the IP network is lower than a threshold. In this paper, we propose a heuristic routing algorithm based on so-called delegating/delegated routers, and evaluate its characteristics using computer simulation considering network-level QoS. The selection of sleep links is determined in terms of the number of traffic paths (called min_used path) or the amount of traffics(called min_used traffic) through those kinks. To our experiment, the min_used traffic method shows a little better energy saving but the increased path length compared to the min_used path method. Those two methods have better energy saving characteristics than the random method. This paper confirms that the delegating/delegated router-based routing algorithm results in energy saving effects and sustains network-level QoS in IP networks.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.8
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• pp.666-671
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• 2000

With the current advances in optical WDM (Wavelength Division Multiplexing) networking technologies and the increasing demand for network bandwidth the Next Generation Internet is expected to be a network that runs IP(Internet Protocol) directly over WDM-based optical networks. The network control architecture for the IP over WDM networks is different from that of traditional Internet since the underlying WDM devices have more constraints than electronic IP routers such as the lack of optical buffers and wavelength continuity property etc. In this paper we introduce several architectural models for implementing IP over WDM networks and propose an integrated network control framework for the IP over WDM networks. This framework leverages the traffic engineering control architecture for the MPLS (Multi-Protocol Label Switching) networks and is mainly developed for the IP over packet-switched WDM networks. We also report several preliminary simulation results of contention resolution schemes in the packet-switched WDM networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.4B
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• pp.387-393
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• 2009

In this paper, we have considered the network performance of the VoIP service with the measurement by an emulator, and analyzed the major factors to affect its performance. Also, we have used the measured values to investigate the traffic variations, where their values were observed in the commercial operated network after the delay, jitter and packet loss, and loss compensation methods were applied as the dominant elements. It is expected that our presented results will be a good data to provide the high-quality of voice service in the Internet.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.69-72
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• 2003

This paper presents a traffic control agent that can perform the dynamic resource allocation by controlling traffic flows on a DiffServ network. In addition, this paper presents a router that can support DiffServ on Linux to support selective QoS in IP network environment. To implement a method for selective traffic transmission based on priority on a DiffServ router, this paper changes the queuing discipline in Linux, and presents the traffic control agent so that it can efficiently control routers, efficiently allocates network resources according to service requests, and relocate resources in response to state changes of the network.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.549-551
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• 2004

This paper used OPNET to simulate video streaming service a test IP network and MPLS network with the traffic shaping that have with CQ_ LLQ algorithm, LSP of fixed bandwidth, policy of limitation users and measures parameters such as delay, throughput, packet loss. To verify the performance of video streaming service in IP network and MPLS network, two scenario that have same topology and traffic source. One is the simulation for best-effort service in pure IP network. The other is the simulation for QoS-enabled service in MPLS Network. Based on simulation result, the MPLS network with CQ_ LLQ algorithm and fixed LSP show advantage of the video streaming service QoS, specially delay and packet loss

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.12
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• pp.520-528
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• 2002

The ATM Forum recently introduced the Guaranteed Frame Rate(GFR) service category GFR service has been designed to support classical best effort traffic such as TCP/IP based traffic. The GFR service not only guarantees a minimum throughput, but also supports fair distribution of available bandwidth to completing VCs. In this paper, we proposed a new buffer management algorithm based on leaky bucket to provide minimum cell rate guarantee and improve fairness. The proposed algorithm reduces complexity and processing overhead of leaky-bucket algorithm to implement easily.

• Journal of Internet Computing and Services
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• v.6 no.4
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• pp.115-124
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• 2005

The packet loss problem that occurs in the mobile multicast (MoM) protocol due to designated multicast service provider(DMSP) handoff is investigated through simulation experiments for several DMSP selection policies. Then, two enhanced DMSP schemes are proposed to minimize the packet loss of the MoM protocol with single DMSP. The first scheme uses a backup DMSP and greatly reduces the packet loss rate at the expense of the increased network traffic. The second scheme utilizes the extended DMSP operation and shows many desirable features such as the almost zero packet loss rate and relatively low network traffic.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.610-612
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• 2001

최근 무선 통신의 빠른 발전과 함께 가까운 미래에는 Mobile사용자에게 다양한 서비스가 제공될 수 있을 것으로 예상된다. 이렇게 다양한 서비스를 제공 받기 위해서 사용자들은 빠른 속도와 연속적인 서비스를 요청하게 된다. 본 논문에서는 Mobile IP상에서 Mobile Host들에게 Prebuffering을 이용하여 연속적인 서비스를 제공해 줄 수 있는 방안을 제시하였다. 기존 연구에서 연속적인 서비스 제공을 위해 제시 한 방안은 인접한 Foreign Network을 모두 그룹으로 설정하고 Prebuffering을 수행하기 때문에 적지않은 Network Traffic이 발생한다. 본 논문에서는 Mobile사용자의 이동 방향을 고려하여 이동 가능성이 있는 Foreign Network만을 그룹으로 설정하기 때문에 Network Traffic을 감소 시킬 수 있다.