• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.5
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• pp.794-804
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• 2018

Various applications running in computers exchange information in the form of packets through the network. Most packets are formatted into UDP/IP or TCP/IP standard. Network management administrators of enterprises and organizations should be able to monitor and manage packets transmitted over the network for Internet traffic measurement & monitoring, network security, and so on. The goal of this paper is to analyze the performance of several algorithms which closely examine and analyze payloads in a DPI(Deep Packet Inspection) system. The main procedure of packet payload analysis is to quickly search for a specific pattern in a payload. In this paper, we introduce several algorithms which detect a specific pattern in payloads, analyze the performance of them from three perspectives, and suggest an application method suitable for requirements of a given DPI system.

• Journal of Information Processing Systems
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• v.2 no.2
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• pp.76-81
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• 2006

A PDA is used mainly for downloading data from a stationary server such as a desktop PC in an infrastructure network based on wireless LAN. Thus, the overall performance depends heavily on the performance of such downloading with PDA. Unfortunately, for a PDA the time taken to receive data from a PC is longer than the time taken to send it by 53%. Thus, we measured and analyzed all possible factors that could cause the receiving time of a PDA to be delayed with a test bed system. There are crucial factors: the TCP window size, file access time of a PDA, and the inter-packet delay that affects the receiving time of a PDA. The window size of a PDA during the downstream is reduced dramatically to 686 bytes from 32,581 bytes. In addition, because flash memory is embedded into a PDA, writing data into the flash memory takes twice as long as reading the data from it. To alleviate these, we propose three distinct remedies: First, in order to keep the window size at a sender constant, both the size of a socket send buffer for a desktop PC and the size of a socket receive buffer for a PDA should be increased. Second, to shorten its internal file access time, the size of an application buffer implemented in an application should be doubled. Finally, the inter-packet delay of a PDA and a desktop PC at the application layer should be adjusted asymmetrically to lower the traffic bottleneck between these heterogeneous terminals.

• Journal of the Korea Computer Industry Society
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• v.2 no.10
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• pp.1269-1284
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• 2001

The Secure Sockets Layer is a protocol for encryption TCP/IP traffic that provides confidentiality, authentication and data integrity. Also the SSL is intended to provide the widely applicable connection-oriented mechanism which is applicable for various application-layer, for Internet client/server communication security. SSL, designed by Netscape is supported by all clients' browsers and server supporting security services. Now the version of SSL is 3.0. The first official TLS vl.0 specification was released by IETF Transport Layer Security working group in January 1999. As the version of SSL has had upgraded, a lot of vulnerabilities were revealed. SSL and TLS generate the private key with parameters exchange method in handshake protocol, a lot of attacks may be caused on this exchange mechanism, also the same thing may be come about in record protocol. In this paper, we analyze SSL protocol, compare the difference between TLS and SSL protocol, and suggest what developers should pay attention to implementation.

• Journal of Advanced Navigation Technology
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• v.19 no.5
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• pp.417-422
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• 2015

A service size of the IoT environment is determined by the number of sensors. The number of sensors increase means increases the amount of data generated by the IoT environment. There are studies to reliably operate a network for research and operational dynamic buffer for data when network congestion control congestion in the network environment. There are also studies of the stream data that has been processed in the connectionless network environment. In this study, we propose a sensor gateway for processing big data of the IoT environment. For this, review the RESTful for designing a sensor middleware, and apply the double-buffer algorithm to process the stream data efficiently. Finally, it generates a big data traffic using the MJpeg stream that is based on the HTTP protocol over TCP to evaluate the proposed system, with open source media player VLC using the image received and compare the throughput performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.9B
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• pp.823-833
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• 2003

To satisfy the requirements of the real-time Internet services, queue management and scheduling schemes should be enhanced to accommodate the delay and jitter characteristic of them. Although the existing queue management schemes can address the congestion problems of TCP flows, they have some problems in supporting real-time services. That is, they show performance degradation when burst traffics are continuously going into the system after the queue is occupied at a predefined threshold level. In addition, under the congestion state, they show large jitter, which is not a desirable phenomenon for real-time transmissions. To resolve these problems, we propose a SDRED (State Dependent Random Early Detection) and dynamic scheduling scheme that can improve delay and jitter performances by adjusting RED parameters such as ma $x_{th}$ and $w_{q}$ according to the queue status. The SDRED is designed to adapt to the current traffic situation by adjusting the max,$_{th}$ and $w_{q}$ to four different levels. From the simulation results, we show that the SDRED decreases packet delays in a queue and has more stable jitter characteristics than the existing RED, BLUE, ARED and DSRED schemes.mes.mes.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.75-84
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• 2014

In order to solve the problems such as overload, single point of failure, non-optimized data path, and network scalability in conventional central mobility management protocols, distributed mobility management schemes have been continually studied in and around the IETF. In this paper, a network-based partially-distributed mobility management mechanism, pDMMv6, is suggested and the performance comparison with traditional protocols such as PMIPv6 and MIPv6 is made through simulation under the various user traffic environment. The simulation results include UDP packet delivery ratio, end-to-end packet delay, binding delay for registration signaling, CPU utilization in each node, and response delays in several server-client TCP applications such as web browsing, e-mail, telnet remote login, FTP file up/down-load, and database access.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.1
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• pp.78-89
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• 2006

In development of network-enabled consumer electronics, much of the time and effort is spent analyzing and solving network performance problems. In this paper, we define an instance of such problems discovered while developing a commercial home network gateway. We then analyze its cause and propose a solution mechanism. Our home network gateway uses art asymmetric link (ADSL) and suffers from an undesirable phenomenon where downlink traffic interferes with upload speed. We call this phenomenon the network performance interference problem. While this problem can easily be confused with receive livelock caused by packet contention at the input queue, we and that this is not the case. By performing extensive experiments and analysis, we reveal that our problem is caused by packet contention at the output queue and certain intrinsic characteristics of TCP. We devise an ACK-separation queuing mechanism for this problem and implement it in the home network gateway Our experiments show that it effectively solves the problem.

• Journal of the Korea Society of Computer and Information
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• v.18 no.10
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• pp.47-54
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• 2013

In this paper, the structural design of optical Internet is analyzed and by using UNI (User Network Interface) signaling protocol an optical transmission experiment was performed. The hierarchical structure of the basic optical Internet consists of the backbone network, the service network and the access network. The necessary functions for each layer were described as follows: Control structure of the optical transport layer, network operation and management structure, internetworking technology of sub networks, routing and signaling technology. By using UNI signaling protocol from OIF (Optical Internetworking Forum), the optical transmission in the proposed structure of the optical Internet network was experimented. By the traffic generation of LSP (Label Switched Path) data packets along the route-configuration was delivered to UNI. Finally, by showing the value of TCP (Transmission Control Protocol) packets the optical transmission was completely and successfully demonstrated.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.12
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• pp.31-36
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• 2005

In this paper, we propose a new optical switching system as a infrastructure of the BcN, in which the high traffic volume will be expected due to the multimedia service, like P2P services. Because the JET protocol, the most popular protocol in OBS (Optical Burst Switching) research area, has high blocking probability for burst, it prevents commercialization in real network for its low throughput in TCP layer. To improve high blocking rate in OBS network, we segment large network into small network and perform burst scheduling to avoid burst loss. By using proposed scheme, Internet provider can reduce network deployment cost in Metro network as well as large mesh core networks

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4B
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• pp.210-217
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• 2005

With rapid advance in wireless communication technologies, many researches are conducted for providing Internet data services while users are roaming around. Efficient management of mobility of mobile nodes is essential as the use of real-time application program grows. In this paper, we propose a multicast-based localized mobility support scheme in IPv6 networks. The proposed scheme utilizes a class of multicast routing protocol for the localized mobility support. Features of the proposed scheme are use of join to a multicast group and leave from that group to localize binding update information and provision of an extended multicast group management mechanism to reduce leave latency. The results of simulation show that the proposed scheme out-performs Mobile IPv6 and Hierarchical Mobile IPv6 in UDP and TCP traffic performance and in wasted bandwidth.