• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.2
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• pp.33-40
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• 2008

Streaming video has become a popular form of transferring media over the wired/wireless network. TCP-friendly rate control (TFRC) is used as a streaming media transport protocol. Using the TCP congestion response function and current network conditions, TFRC adjusts its sending rate to yield the maximum TCP-friendly throughput. Since TFRC was designed for applications that would prefer to maintain a slowly-changing sending rate, it is less responsive to changes in handover between wireless heterogeneous networks such as 3G network, WLAN, and so on. This paper shows a new TFRC method for vertical handover over wireless heterogeneous network. The proposed TFRC method has features of low quality interruption and fast rate adaptation to a new target network. The simulation results show that the proposed one provides better QoS and throughput support than the traditional TFRC scheme during vertical handover.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.12
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• pp.69-77
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• 2010

This paper presents a fast IP mobility management scheme in heterogeneous networks using the multiple wireless network interlaces. More specifically, in order to minimize the packet loss and handover latency due to handover, the E-HMIPv6, IETF HMIPv6 has been extended, is presented where the multiple tunnels between E-MAP and mobile node are dynamically constructed. E-HMIPv6 is composed of the extension of IETF HMIPv6 MAP, handover procedure, and simultaneous multiple tunnels. In order to demonstrate superior to the proposed method, the NS-2 simulation has done for performance evaluation of TCP and UDP-based application comparison with the existing mobility management method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.2B
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• pp.1-10
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• 2005

TCP/IP protocols have been implemented in software program running on CPU in end systems. As the increased demand of fast protocol processing, it is required to implement the protocols in hardware, and Host Interface is responsible for communication between external CPU and the hardware blocks of TCP/IP implementation. The Host Interface follows AMBA AHB specification for the communication with external world. For control flow, the Host Interface behaves as a slave of AMBA AHB. Using internal Command/status Registers, the Host Interface receives commands from CPU and transfers hardware status and header information to CPU. On the other hand, the Host Interface behaves as a master for data flow. Data flow has two directions, Receive Flow and Transmit Flow. In Receive Flow, using internal RxFIFO, the Host Interface reads data from UDP FIFO or TCP buffer and transfers data to external RAM for CPU to read. For Transmit Flow, the Host Interface reads data from external RAM and transfers data to UDP buffer or TCP buffer through internal TxFIFO. TCP/IP hardware blocks generate packets using the data and transmit. Buffer Descriptor is one of the Command/Status Registers, and the information stored in Buffer Descriptor is used for external RAM access. Several testcases are designed to verify TCP/IP functions. The Host Interface is synthesized using the 0.18 micron technology, and it results in 173 K gates including the Command/status Registers and internal FIFOs.

• Journal of Korea Game Society
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• v.10 no.6
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• pp.147-155
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• 2010

On this paper, suggests a communication structure making possible to fast data send-receive for the gaming process synchronization. For these things, first of all, analyze the data send-receive speed effecting on the online game by the game genre. Moreover, we suggested a proper data communication structure like real-time online action game genre which gaming synchronization effects on the gaming process. Communication structure suggested on this paper is being used with TCP/UDP protocol, and it is applied to the network system and verify improved data send-receive speed. These data send-receive structure can be applied to the various online games.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5B
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• pp.413-420
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• 2006

HMIPv6 is designed to reduce the signaling load to external network and improve handover speed of MN by including Mobility Anchor Point(MAP) in local handover. However in this case of macro handover, it's just used pervious MIPv6 handover algorithm. So, it occurs packet loss and transmission delay problem. In this paper, we propose the mechanism applying the HMIPv6 for Fast Handover to choose suitable to the condition buffering handover. The condition for the selection is result distance measurement between MN and CN, between MN and NAR. Furthermore, using F-SNOOP protocol, it is possible to improve wireless network performance. Wireless network has high Bit Error Rate(BER) characteristic because of path loss, fading, noise and interference. TCP regards such errors as congestion and starts congestion control. This congestion control makes packet transmission rate low. However, F-SNOOP improves TCP performance based on SNOOP and Freeze TCP that use Zero Window Advertisement(ZWA) message when handoff occurs in wireless network.

• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.1
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• pp.159-169
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• 1999

Recently a firewall is being employed to protect hacking by controlling the traffics. The security services in the firewall include authentication, access control, confidentiality, integrity, and audit trail. A token is adapted for authentication to the firewall. A token has a small battery within which has restricted power capacity, This paper proposes a novel cost-effective firewall token for hacking protecting on transmission control protocol/internet protocol (TCP/IP) based network. This paper proposes a fast exponentiation method with a sparse prime that take a major operation for a public-key crypto-system and a major power consumption in the token. The proposed method uses much less amount of modular operations in exponentiation that is reduced of battery's capacity or CPU's price in the token.

• KSCI Review
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• v.15 no.1
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• pp.53-64
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• 2007

Avoid at damage systems in order to avoid own IP address exposure, and an invader does not attack directly a system in recent hacking accidents at these papers, and use Stepping stone and carry out a roundabout attack. Use network audit Policy and use a CIS, AIAA technique and algorithm, the Sleep Watermark Tracking technique that used Thumbprints Algorithm, Timing based Algorithm, TCP Sequence number at network bases, and Presented a traceback system at TCP bases at log bases, and be at these papers Use the existing algorithm that is not one module in a system one harm for responding to invasion technology develop day by day in order to supplement the disadvantage where is physical logical complexity of configuration of present Internet network is large, and to have a fast technology development speed, and presentation will do an effective traceback system.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2003.05a
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• pp.311-315
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• 2003

Recently, there is asymmetrical transmission in Internet data stream. The asymmetrical transmission has much more downstream than upstream. Owing to this point, it needs to reduce the acknowledgement as element of the obsrtuction in downstream. In this paper, according to simulation's result, we know that Sack has good performance than New Reno in bottleneck environment Comparing two protocols in packet loss rate, NewReno is lower than Sack. And also comparing two protocols in throughput of ack packet, not only NewReno processes ack packet more quickly than Sack, but also NewReno processes more ack packet than Sack protocol during ten seconds in simulation. As a result, NewReno is batter than Sack in throughput of asymmetrical link.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.189-189
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• 2004

• Journal of KIISE:Computer Systems and Theory
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• v.30 no.7_8
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• pp.331-340
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• 2003

Low-cost commodity SMP(Symmetric Multiprocessor) is widely used as a node of cluster system. In this paper, we implement and evaluate the performance of SDSM system for SMP clusters. Our SDSM system provides HLRC(Home-based Lazy Release Consistency) memory consistency model. Our protocol utilize shared memory within same SMP node, so that page fetch and message passing through network can be reduced. It is implemented on 8 node of 2-way Pentium-III SMP interconnected with 100Mbps Fast Ethernet, and uses TCP/IP for transport/network layer protocol. The experiment with eight applications shows that our SMP protocol achieves maximum 33% speedup improvement and 13%-52% reduction of page fetch compared with uniprocessor protocol.