• Proceedings of the Korea Information Processing Society Conference
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• 2002.04b
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• pp.1483-1486
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• 2002

Multicast protocols are efficient methods of group communication, but they do not support the various transmission protocol services like a reliability guarantee, FTP, or Telnet that TCPs do. The purpose of this dissertation is to find a method to utilize sewer routers to form multicasts that can simultaneously transport multicast packets and TCP packets. For multicast network scalability and error recovery the existing SRM method has been used. Three packets per TCP transmission control window size are used for transport and an ACK is used for flow control. A CBR and a SRM is used for UDP traffic control. Divided on whether a UDP multicast packet and TCP unicast packet is used simultaneously or only a UDP multicast packet transport is used, the multicast receiver with the longest delay is measured on the number of packets and its data receiving rate. It can be seen that the UDP packet and the TCP's IP packet can be simultaneously used in a server router.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.6
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• pp.177-182
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• 2011

These days as there are growing the number of vessel sailing, diverse aquaculture industries, fishing works, and leisure activities in coastal area, the diverse communication services have been required for secure voyage information. This paper addresses the scheme for costal area service using mobile IP router with multiple interfaces. For this, this system has the wireless interfaces, such as WiBro, HSDPA, and WLAN that can provides vessels with divers communication services, and can provide the vessels with the diverse information communication services in real-time through wireless communication network installed in costal area. So this can provide the infrastructure that supplies the authorized seamless information communication services.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.9A
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• pp.663-668
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• 2003

With the advent of high speed networking technology, computers connected to the high-speed networks tend to consume more of their CPU cycles to process data. So one of the solutions to improve the performance of the computers is to reduce the CPU cycles for processing the data. As the consumption of the CPU cycles is increased in proportion to the number of the packets per second to be processed, reducing the number of the packets per second by increasing the length of the packet is one of the solutions. In order to meet this requirement, two types of jumbo packets such as jumbograms and jumbo frames have already been standardized or being discussed. In case that the jumbograms and general packets are interleaved and scheduled together in a router, the jumbogrms may deteriorate the QoS of the general packets due to the transfer delay. They also frequently exhaust the memory with storing the huge length of the packets. This produces the congestion state easily in the router that results in the loss of the packets. In this paper, we analyze the problems in processing the jumbo packets and suggest a noble solution to overcome the problems.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1997.03a
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• pp.163-181
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• 1997

This dissertation provides a theroetic study on the network security in general , the firewall in particular . In fact, the firewall has been recognized as a very promising option to obtain the security in the real world network environment . The dissertation provides a thorough theoretic investigation on the various problems raised in the computer network, and also explores a methodology of the security against IP spoofing. Moreover, it investigates a systematic procedure to make analysis plans of the firewall configuration. Based on the above investigation and analysis , this dissertation provides two approaches to network security, which address a number of issues both at the network and at application level. At the network level. a new methdo is proposed which uses packet filtering based on the analysis of the counter plot about the screen router. On the other hand at the application level, a novel method is exlored which employs security software , Firewall-1, on Bastion host. To demonstrate the feasibility and the effectiveness of the proposed methodologes, a prototype implementation is made. The experiment result shows that the screen router employing the proposesed anti-IP spoofing method at the network level is effective enough for the system to remain secure without being invaded by any illegarl packets entering from external hackers. Meanwhile , at the application level. the proposed software approach employing Firewall -1 is proved to be robust enough to provent hackings from the outer point to point protocol connection. Theoretically, it is not possible to provide complete secuirty to the network system, because the network security involove a number of issues raised from low level network equipments form high level network protocol. The result in this dissertation provides a very promising solution to network security due to its high efficiency of the implementation and superb protectiveness from a variety of hacking.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2B
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• pp.158-166
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• 2004

Address lookup is one of the most essential functions of the Internet routers and a very important feature in evaluating router performance. Due to the facts that the Internet traffic keeps growing and the number of routing table entries is continuously growing, efficient address-lookup mechanism is indispensable. In recent years, various fast address-lookup schemes have been proposed, but most of those schemes are not practical in terms of the memory size required for routing table and the complexity required in table update In this paper, we have proposed a parallel IP address lookup architecture based on multiple hashing. The proposed scheme has advantages in required memory size, the number of memory accesses, and table update. We have evaluated the performance of the proposed scheme through simulation using data from MAE-WEST router. The simulation result shows that the proposed scheme requires a single memory access for the address lookup of each route when 203kbytes of memory and a few-hundred-entry TCAM are used.

• The KIPS Transactions:PartC
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• v.14C no.3 s.113
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• pp.267-276
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• 2007

In OSPF, the larger and more unstable the area, the greater the likelihood for performance problems associated with routing protocol recalculation. Generally, an area should have no more than 50 routers. Areas with unstable links should be smaller. Military tactical data network is used for military operations during war-time. It consists of wireless network for mobility of node. Thus, it has low-bandwidth and unstable property. In addition, it is expected that many kinds of router-failure, Link-failure and recovery at emergency period. However, Military tactical data network is designed with about one and half times the number of recommendation. This paper proves that the traffic is limited by the increase of re-calculation of area.

• Journal of Korea Society of Industrial Information Systems
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• v.2 no.1
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• pp.103-123
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• 1997

This dissertation provides a theoretic study on the network security in general , the firewall in particular. In fact the firewall has been recognized as a very promising option to obtain the security inthe real work network environment . The dissertation provides a throuth theoretic investigation on the various problems raised in the computer network, and also explores a methodology of the security against IP spoofing. Moreover, it investigates a systematic procddure to make analysis and plans of the firewall configuration . Based on the above investigation and analysis, this dissertation provides two approaches to network security , which address anumber of issuesboth at the network and at applicatino level. At the network level, a new method is proposed which uses packet filtering based on the analysis of the counter plot about the screen router.On the other hand, at the application level, a novel method is explored which employs secureity software. Firewall-1 , on Bastion host. To demonstrate the feasibililty and the effectiveness of the proposed methodologties , a prototype implementation is made The experiment result shows that the screen router employing the proposed anti-IP spoofing method at the network level is effective enough for the system to remain secure without being invaded by any illegal packets entering form external hackers. Meanwhile , at the application level, the proposed software approach employing Firewall-1 is proved to be robust enugh to prevent hackings from the outer point the point protocal connnection . Theoretically, it is not possible to provide complete security to the network system, because the network security involve a number of issues raised form low level network equipments form high level network protocol. The result inthis dissertation provides a very promising solution to network security due to its high efficiency of the implementation and superb protectiveness from a variety of hacking.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.179-186
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• 2012

Nowadays, the multihomed host equipped with multiple network interfaces has been interested research in next generation wireless network, because the mobile users expect that they can be able to access services not only anywhere, at any time and from any network but also simultaneously. This paper addresses the mobility simulation model of the multihomed node for supporting MIPv4 and MIPv6 function in an interworking of Worldwide Interoperability for Microwave Access (WiMAX) and IEEE 802.11 WLAN. The multihomed node with two air interfaces has been developed based on WiMAX and WLAN workstation node model in simulation software. The main point of the developed model is to support both MIPv4 and MIPv6 function, and provide network selection policy for the multihomed node between WiMAX and WLAN network. Based on the received Router Advertisement along with the interface number, we can manage the access interfaces in ordered list to make handover decision while the multihomed node is moving. In the end of this paper, the simulation scenarios and results are shown for testing MIPv4 and MIPv6 function.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.12
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• pp.120-127
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• 2008

HMIPv6 draws lots of attentions in recent years for providing an efficient handover and reducing the signaling overhead. HMIPv6 employs MAP(Mobility Anchor Point) in order to minimize a signaling overhead and a local mobility management. MAP completes an efficient mobility management in HMIPv6 network environment with frequent handover. However, HMIPv6 causes load concentration at a paricular MAP and may have unnecessary latency between HN(Mobile Node) and CN(Correspondent Node) within the same network. A MAP may also disturb the route optimization in HMIPv6 network because all packets must be transmitted through a MAP. In this paper, we propose a scheme to optimize the route in HMIPv6 networks according to MAP load. We configure a threshold in order to support the better service into MAP domain. The packets do not pass through MAP and are directly transmitted to AR(Access Router) if the number of current MNs attached to the MAP exceed the desired threshold. We simulate the performance of the proposed scheme and compare with HMIPv6. Resultly, the proposed scheme reduces signaling costs and mitigates concentration of a paticular MAP as well.

• The KIPS Transactions:PartC
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• v.15C no.4
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• pp.253-262
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• 2008

Providing Quality-of-Service (QoS) guarantee requires the reservation of resource needed to accommodate the traffic flow of service for which resource reservation protocol (RSVP) was introduced. However, if any RSVP-capable router on the path fails to accommodate the traffic flow due to lack of resource, the flow is not allowed no matter how much surplus resources other routers on the path have. In order to solve this problem, this paper proposes a resource reservation method with available resource migration between RSVP-capable routers in which the routers use the recently developed latency optimized fair queuing scheduler. The results of the simulation applying the proposed method to an evaluation network show that it may yield the gain of up to 165% compared to that in the original one in terms of the number of admitted flows.