• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.3
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• pp.46-52
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• 2008

BGP is an exterior routing protocol which exchanges routing information between ASs in ISP or large networks. It is necessary for the BGP to provide traffic enforcement among ASs, for an End-to-End traffic engineering capability in the Internet. However, traditional BGP-4 is lack of end-to-end traffic engineering capability because the policy-based routing affects the traffic only between directly-connected neighbor ASs. This paper proposes an extended BGP routing algorithm to achieve an End-to-End traffic engineering capability. This new method does not require an additional BGP message type, nor change a structure of existing routing table. It only extended the operation of UPDATE message with AS_PATH attribute, which is well-known mandatory. Simulation shows that the new BGP algorithm improves the packet delay and packet loss without the problem of backward compatibility.

• Journal of KIISE
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• v.44 no.8
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• pp.749-759
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• 2017

The weapon system based on voice call can cause delay, error or damage to the message during the exchange of information. Furthermore, since the weapon system has a unique message format, it has limited data distribution. Therefore, a Korea Variable Message Format(KVMF) has been developed in this study to utilize a standard sized data format to guarantee the transmission quality and minimize the transmission amount. The ground tactical data link system quickly and accurately shares tactical information by incorporating a field management system that utilizes the KVMF standard message in the mobile weapon system. In this study, we examine the possibility of performing the mission immediately by recovering the state of network joining when a normal/abnormal termination situation of the battlefield management system occurs.

• The Journal of the Korea Contents Association
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• v.6 no.2
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• pp.84-92
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• 2006

In this paper, we propose an efficient multicasting algorithm in multistage interconnection networks (MIN's) employing the region encoding scheme. The proposed algorithm uses the recursive scheme to recycle a multicast message at most two times through MIN, in order to send it to its desired destinations. It is composed of two recycling phases which are the copying phase and the routing phase of the multicast message. In the first phase, a source sends the message to a region that contains the largest number of destination regions, and destinations in these regions receive and store the message in this phase. The remaining destinations can finally receive the message in the second phase. This method of the algorithm can improve its performance by reducing the delay of message and the volume of traffic. Moreover, we evaluate the performance of our algorithm in terms of the average number of recycling and the number of internal links used per destination, comparing with the previously proposed algorithm.

• Journal of the Korea Society of Computer and Information
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• v.15 no.7
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• pp.41-47
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• 2010

The emergency between vehicles on the superhighway should be transmitted quickly to the following vehicles for safety of people. The message between them has been transmitted by broadcast method in an wireless environment of 802.11, so far. That causes the broadcast storm and a waste of the bandwidth of Wireless network owing to unnecessary process of sending messages to even vehicles that do not have to receive the information. The message collision is a main cause of the increase of message delay. In order to overcome the existing problem, this paper proposed a message broadcast scheme based on cell (MBC), which is the way to divide cars into different groups by cell unit and transmit messages to the members of the groups through the cell primary (cp) vehicles. This paper shows the proposed broadcast's performance in the same environment is much superior to other conventional broadcast schems for inter-vehicle communication, since the receiving ratio among the following vehicles is improved.

• The Transactions of the Korea Information Processing Society
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• v.4 no.7
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• pp.1797-1803
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• 1997

Message handling function of the SS7(Signaling System N0.7) provides signaling traffic routing capabilities to transfer the signaling traffic to the destination nodes in the signaling network. This message handling function should be handled without any transfer delay for real time processing of large amount of signaling traffic for data communication service, and visual information service. In this paper, we suggest two routing algorithms working on the distributed message handling processors which were specially designed for message handling function. The one is an internal distributing algorithm for equal distribution of signaling traffic among the distributed message handling processors and the other is a distributing algorithm for distribution of signaling traffic in the multiple signaling routes. Both of algorithms are using signaling link selection codes labled in each signaling messages. It is shown that the suggested algorithms are very efficient for routing signaling traffic at the fault condition of signaling routes and the restoration of unavailable signaling routes.

• Journal of Digital Contents Society
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• v.15 no.2
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• pp.137-145
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• 2014

In this paper, we focus on end-to-end transfer delay improvement by using erasure coding when delivering expediting message consisting of M packets in networks with high coefficient of variation of transfer time. In the scheme, M packets are divided into b groups with each having g packets. Each group is erasure coded with additional r packets and transmitted. Since the first arrived g packets among g+r packets completes the delivery of the group, the delivery time of the expediting message is reduced. For the scheme, we investigate the optimum group size and number of redundancy packets considering delivery delay reduction and additional transmission cost caused by using erasure coding. From the results of the investigation, we see that the proposed scheme is effective in networks having high variability of transfer time and would be very useful and practical especially for the case that expedited deliveries of messages are needed.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.11
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• pp.9-16
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• 2012

In this paper, we focus on end-to-end transfer delay improvement by using network coding and propose a scheme where a message is divided into several packets which are network coded generating additional redundancy with the results that the number of transmitted packets increases. In networks with high coefficient of variation of transfer time, increased number of packets could reduce the transfer time of the message to a destination. For the proposed scheme, we investigate the optimum number of divided packets and redundancy considering transfer delay reduction and additional transmission cost caused by using network coding under the restriction of maximum transmission packet size. From the results of the investigation, we see that the proposed scheme is effective in networks having high variability of transfer time and would be very useful and practical especially for the case that expedited deliveries of messages are needed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.309-314
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• 2006

In general DGPS system, the correction message is transferred to users by wireless modem. To cover wide area, many DGPS station should be needed. And DGPS users must have a wireless modem that is not necessary in standalone GPS. But SBAS users don't need a wireless modem to receive DGPS corrections because SBAS correction message is transmitted from the GEO satellite by L1 frequency band. SBAS signal is generated in the GUS(Geo Uplink Subsystem) and uplink to the GEO satellite. This uplink transmission process causes two problems that are not existed in GPS. The one is a time delay in the uplink signal. The other is an ionospheric problem on uplink signal, code delay and carrier phase advance. These two problems cause ranging error to user. Another critical ranging error factor is clock synchronization. SBAS reference clock must be synchronized with GPS clock for an accurate ranging service. The time delay can be removed by close loop control. We propose uplink ionospheric error correcting algorithm for C/A code and carrier. As a result, the ranging accuracy increased high. To synchronize SBAS reference clock with GPS clock, I reviewed synchronization algorithm. And I modified it because the algorithm didn't consider doppler that caused by satellites' dynamics. SBAS reference clock synchronized with GPS clock in high accuracy by modified algorithm. We think that this paper will contribute to basic research for constructing satellite based DGPS system.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.6
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• pp.25-35
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• 1998

The control system architecture in switching systems have undergone numerous changes to provide various call processing capability needed in telecommunication services. During call processing in a distributed switching control environment, the delay effect due to communication among main processors or peripheral controllers is one of the limiting factors which affect the system performance. In this paper, we propose a performance model for an IPC(Inter Processor Communication) interface hardware block which is required on the ATM cell-based message processing in a distributed ATM exchange system, and analyze the primary causes which affect the processor performance through the simulation. Consequently, It can be shown that the local CPU of the several components(resources) related to the IPC scheme is a bottleneck factor in achieving the maximum system performance from the simulation results, such as the utilization of each processing component according to the change of the input message rate, and the queue length and processing delay according to input message rate. And we also give some useful results such as the maximum message processing capacity according to the change of the performance of local CPU, and the local CPU maximum throughput according to the change of average message length, which is applicable as a reference data for the improvement or expansion of the ATM control system.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.2
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• pp.149-156
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• 2005

The HLA is the simulation architecture standard that the civilian and military simulation communities are deeply interested in. We can find various successful practices applying HLA to constructive simulations such as war games in domestics and overseas. However, any case of real-time distributed simulations has not been reported. The reason is that a message transmission period via RTI in a network layer varies according to computing power, simulation nodes, transmission types, and packet size; further a message processing time in an application layer depends on its processing methods, thus too difficult to set up real-time constraints for the enhancement of a real-time resolution. Hence, in this paper we have studied the real-time constraints of RTI for the development of the M-SAM simulator. Thus we have developed a HLA based pilot simulator using 6 PC's in LAN and then measured and analysed the performance of the RTI. As the results of our work, we could obtain the quantitative values for message delay, RTI overhead and RTI packet transmission ratio by a real operation scenario and loads, which are not shown in the previous works. We also expect that the results can be used as a guideline to set up the number of targets, transmission frequency and message processing method in the development of the M-SAM simulator and similar applications.