• Proceedings of the IEEK Conference
• /
• 2003.07b
• /
• pp.927-930
• /
• 2003

In this paper, a design of processor IP for TCP/IP protocol stack is described. The processor consists of input and output buffer memory with dual bank structure, 32-bit RISC microprocessor core, DMA unit with on-the-fly checksum capability. To handle the various modes of TCP/IP protocol, hardware and software co-design approach is used rather than the conventional state machine based design. To eliminate delay time due to the data transfer and checksum operation, DAM module which can execute the checksum operation on-the-fly along with data transfer operation is adopted. By programming the on-chip code ROM of RISC processor differently. the designed stack processor can support the packet format conversion operations required in the various TCP/IP protocols.

• International Journal of Control, Automation, and Systems
• /
• v.3 no.1
• /
• pp.122-129
• /
• 2005

We describe the MiniWeb[7] TCP/IP stack (mIP), which is an extremely small implementation of the TCP/IP protocol suite running 8 or 32-bit micro controllers intended for embedded control systems, and satisfying the subset of RFC1122 requirements needed for host­to-host interoperability over different platforms. Our TCP/IP implementation does sacrifice some of TCP's mechanisms such as fragmentation, urgent data, retransmission, or congestion control. Our implementation is applicable to web based controllers. The network protocols are tested in operational networks using CommView and Dummynet where the various operational parameters such as bandwidth, delay, and queue sizes can be set and controlled.

• Information and Communications Magazine
• /
• v.32 no.9
• /
• pp.31-36
• /
• 2015

TCP (Transmission Control Protocol)는 IP (Internet Protocol)와 더불어 인터넷 핵심 프로토콜 중 하나로써, 현재 Web, e-mail, FTP 등 대다수의 애플리케이션에서 사용되고 있는 연결 지향적이고 신뢰성 전송을 보장하는 전송 계층 프로토콜이다. 유/무선 네트워크가 진화함에 따라 TCP 역시 보다 나은 서비스를 제공하기 위해 많은 연구가 이루어졌고, 이를 통해 최근에는 스트리밍과 같이 지연이 중요한 애플리케이션에서도 많이 사용되고 있다. 본 논문은 모바일 데이터가 폭증함에 따라 무선 네트워크에서의 TCP 성능이 큰 관심을 받고 있는 현 시점에서 최근에 이슈가 되고 있는 무선 네트워크에서 bufferbloat문제의 심각성과 이를 해결하기 위한 방안에 대해 다룬다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.12B
• /
• pp.1106-1114
• /
• 2003

Several analytic models describe transmission control protocol (TCP) performance such as steady-state throughput as an averaged ratio of number of transmissions to latency. For more detailed analysis of TCP latency, the latency during packet losses are recovered should be considered. In this paper, we derive the expected duration of loss recovery latency considering the number of packet losses recovered by retransmissions. Based on the numerical results verified by simulations, TCP using selective acknowledgement (SACK) option is more effective than TCP NewReno from the aspect of loss recovery latency.

• Journal of Navigation and Port Research
• /
• v.41 no.6
• /
• pp.395-400
• /
• 2017

As a serial communications protocol, Modbus has become a practically standard communication protocol and is now a commonly available means of connecting industrial electronic devices. Therefore, all devices can be connected using the Modbus protocol with the measurement and remote control on ships, buildings, trains, airplanes and more. The existing Modbus that has been used is based on serial communication. Modbus TCP uses Ethernet communication based on TCP / IP which is the most widely used Internet protocol today; so, it is faster than serial communication and can be connected to the Internet of Things. In this paper, we designed an algorithm to control LED lighting in a wireless Wi-Fi environment using the Modbus TCP communication protocol, and designed and implemented a LED controller circuit that can check external environmental factors and control remotely through the integrated management system of a ship. Temperature, humidity, current and illuminance values, which are external environmental factors, are received by the controller through the sensors, and these values are communicated to the ship's integrated management system via the Modbus protocol. The Modbus can be connected to Master devices via TCP communication to monitor temperature, humidity, current, illuminance status and LED output values, and also users can change the RGB value remotely in order to change to the desired color. In addition, in order to confirm the implementation of the controller, we developed a simulated ship management system to monitor the temperature, humidity, current and illumination conditions, and change the LED color of the controller by changing the RGB value remotely.

• Journal of the Korea Society for Simulation
• /
• v.18 no.3
• /
• pp.123-131
• /
• 2009

Wireless networks have several unique features : node mobility, restricted bandwidth, time-variable bandwidth, large latency, and high bit error rates time due to channel fading. These features at wireless networks intend to decrease the performance TCP protocols are used in wireless networks. Lots of studies have been done for finding appropriate wireless transport protocols for current wireless communications. However, related studies have not provided good performance or some protocols have a good performance only in specific circumstances. Thus, these are not suitable for general wireless circumstance. Therefore, we propose a new wireless transport protocol which provides better performance than the previous ones. And we'd like to solve a problem that previous protocols cannot maintain their connections even though they have multiple paths until another path is successfully set up. To solve these problems, a new protocol ATP-M is proposed which is designed on already known TCP-M and ATP protocols. With NS-2 computer simulation, it is shown that this newly proposed protocol has better system throughput than TCP, TCP-M and ATP protocols.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.1 no.2
• /
• pp.131-136
• /
• 2008

From the reciprocal connection by this Internet network researchs about the efficiency improvement of the whole system is accomplished with the method which reduces delays in message transmission. From here, we will do a comparative study between the user data program protocol (UDP) and the zero copy which does not use the buffer cache to fine out the valid method to improve the efficiency. In this thesis, I will change the message copy from execution process of the buffer cache of the TCP/IP on Unix OS with process on Linux OS. The object of conversion is to show you that the zero copy which doesn't use the buffer cache from transfer control class improves the communication efficiency.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.5
• /
• pp.1139-1145
• /
• 2010

Wireless mesh network is similar to ad-hoc network, so when transferred to the data packet in the wireless environment, interfered factor arise. When TCP(Transport Control Protocol) was created, however as it was design based on wired link, wireless link made more transmission error than wired link. It is existent problem that TCP unfairness and congestion collapse over wireless mesh network. But packet losses due to transmission errors are more frequent. The cause of transmission error in wireless ad-hoc network may be inexactly regarded as indications of network congestion. And then, Congestion Control Algorithm was running by this situation causes the TCP performance degradation. In this paper, proposed TCP can adaptively regulate the congestion window through moving node in the Wireless Mesh Network. And it enhanced the performance.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.12 no.8
• /
• pp.1391-1400
• /
• 2008

In recent yeats, SCTP is known as the next transport layer protocol for connection-oriented and reliable data transfer after TCP/UDP. The SCTP was developed on the basis of the existing TCP and was designed to eliminate defects of TCP. SCTP has the different characteristic of multi-streaming and multi-homing from TCP. In this paper, we studied the defects of the performance of communication using the traits of multi-homing. And we evaluated the efficiency for each application services on the basis of SCTP of IPv6. Also, we analysed the delay time of a packet using SCTP and TCP. We noticed that the efficiency of SCTP is better than that of TCP.

• Journal of Communications and Networks
• /
• v.12 no.5
• /
• pp.499-509
• /
• 2010

A plethora of transmission control protocol (TCP) congestion control algorithms have been devoted to achieving the ultimate goal of high link utilization and fair bandwidth sharing in high bandwidth-delay product (HBDP) networks. We present a new insight into the TCP congestion control problem; in particular an end-to-end delay-based approach for an HBDP network. Our main focus is to design an end-to-end mechanism that can achieve the goal without the assistance of any network feedback. Without a router's aid in notifying the network load factor of a bottleneck link, we utilize goodput and throughput values in order to estimate the load factor. The obtained load factor affects the congestion window adjustment. The new protocol, which is called TCP-goodput and throughput (GT), adopts the carefully designed inversely-proportional increase multiplicative decrease window control policy. Our protocol is stable and efficient regardless of the link capacity, the number of flows, and the round-trip delay. Simulation results show that TCP-GT achieves high utilization, good fairness, small standing queue size, and no packet loss in an HBDP environment.