• ETRI Journal
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• v.43 no.1
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• pp.64-73
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• 2021

Two-dimensional torus network nodes are typically interconnected using XY routing algorithm for transmitting a packet from a source node to a destination node. In XY routing, if all the paths are used efficiently, the throughput and latency can be improved. In this paper, to utilize all the paths efficiently, we propose a novel binary optical routing algorithm (BORA) to improve the throughput and latency. The throughput is calculated according to the injection rate and number of packets received at the destination. The XY routing algorithm and proposed BORA are implemented using objective modular network testbed in C++ simulation software and the results are analyzed and compared. In this paper, the simulation results show that the network latency reduces to 50% while using the proposed algorithm; moreover, the throughput is also improved.

• 한국정보통신설비학회:학술대회논문집
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• 2006.08a
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• pp.43-46
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• 2006

IEEE 802.16 WirelessMAN aiming to broadband wireless access (BWA) is evolving to 4G mobile communication system through the standardization of IEEE 802.16e supporting mobility on existing fixed WirelessMAN system. It is necessary for hand-over to provide seamless data service while MS (Mobile Station) moves to another BS (Base Station). Because the performance of handover affects packet loss or delay of any communications, it must consider low latency handover mechanism in packet based network. In this paper, we describes handover scheme of IEEE 802.16e with the cell edge interference problem and shows the way to solve the problem in frequency reuse one deployment. Our scheme reduces the handover latency and packet loss probability.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.63-66
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• 2007

Everytime a node moves out, the connection makes handover which occurs much latency. In NetLMM(Network based Localized Mobility Management), network supports the mobility management for nodes and it improves handover latency using MIH(Media Independent Handover) service. In this paper, we shall analyse and improve the handover latency with addition of some messages to NetLMM protocol.

• Journal of information and communication convergence engineering
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• v.6 no.3
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• pp.245-248
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• 2008

Everytime a node moves out of its area, the connection to the node encounters a handover which may cause much latency. NetLMM(Network based Localized Mobility Management) supports the mobility management for such nodes and improves handover latency using MIH(Media Independent Handover) function. In this paper, we add some messages to NetLMM procedure to improve handover latency and analyze its effects through a scenario based approach

• IEMEK Journal of Embedded Systems and Applications
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• v.15 no.6
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• pp.299-305
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• 2020

We have developed a scheduler that additionally consider network performance by extending the Kubernetes developed to manage lots of containers in cloud computing nodes. The network delay adapt characteristics of the compute nodes were learned during server operation and the learned results were utilized to develop placement algorithm by considering the existing measurement units, CPU, memory, and volume together, and it was confirmed that the low delay network service was provided through placement algorithm.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.3
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• pp.59-64
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• 2023

Fire and disaster broadcasting systems are divided into analog, digital, and network-based digital public address systems, and important specifications in network-based digital public address systems are low-latency audio, high sampling rate, and multi-channel input and output. In the past, it has been widely used to the AoE method for distinguishing based on the MAC address of the data link layer. However, this method has a problem of increasing complexity and cost. This proposal is an AoIP/UDP method, which allows communication to be easily distinguished by IP address without the need for a separate redundant network, so that the network can be freely used and configured, and cost can be reduced by reducing complexity. After implementing the AoIP/UDP method, the experimental results showed that the cost was improved with the equivalent performance with 2.66ms latency.

• Journal of Communications and Networks
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• v.17 no.3
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• pp.306-320
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• 2015

Due to an explosive growth in services running in different datacenters, there is need for service selection and routing to deliver user requests to the best service instance. In current solutions, it is generally the client that must first select a datacenter to forward the request to before an internal load-balancer of the selected datacenter can select the optimal instance. An optimal selection requires knowledge of both network and server characteristics, making clients less suitable to make this decision. Information-Centric Networking (ICN) research solved a similar selection problem for static data retrieval by integrating content delivery as a native network feature. We address the selection problem for services by extending the ICN-principles for services. In this paper we present Queue and Latency, a network-driven service selection algorithm which maps user demand to service instances, taking into account both network and server metrics. To reduce the size of service router forwarding tables, we present a statistical method to approximate an optimal load distribution with minimized router state required. Simulation results show that our statistical routing approach approximates the average system response time of source-based routing with minimized state in forwarding tables.

• ETRI Journal
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• v.40 no.1
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• pp.72-88
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• 2018

In the fifth generation (5G) era, the radio internet protocol capacity is expected to reach 20 Gb/s per sector, and ultralarge content traffic will travel across a faster wireless/wireline access network and packet core network. Moreover, the massive and mission-critical Internet of Things is the main differentiator of 5G services. These types of real-time and large-bandwidth-consuming services require a radio latency of less than 1 ms and an end-to-end latency of less than a few milliseconds. By distributing 5G core nodes closer to cell sites, the backhaul traffic volume and latency can be significantly reduced by having mobile devices download content immediately from a closer content server. In this paper, we propose a novel solution based on software-defined network and network function virtualization technologies in order to achieve agile management of 5G core network functionalities with a proof-of-concept implementation targeted for the PyeongChang Winter Olympics and describe the results of interoperability testing experiences between two core networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8A
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• pp.600-609
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• 2009

The traditional carrier sense multiple access (CSMA) protocol like IEEE 802.11 Distributed Coordination Function (DCF) does not handle the constraints adequately, leading to degraded delay latency and throughput as the network scales are enlarged. We present more efficient method of a medium access for real-time wireless sensor networks. Proposed MAC protocol is like the randomized CSMA protocol, but unlike previous legacy protocols, it does not use a time-varying contention window from which a node randomly picks a transmission slot. To reduce the latency for the delivery of event reports, we carefully decide to select a fixed-size contention window with non-uniform probability distribution of transmitting in each slot. We show that the proposed method can offer up to severaansimes latency reduction compared to legacy of IEEE 802.11 as the size of the sensor network scales up to 256 nodes using widely using network simulation package,caS-2. We finally show that proposed MAC scheme comes close to meet bounds on the best latency being achieved by a decentralized CSMA-based MAC protocol for real-time wireless sensor networks which is sensitive to delay latency.

• 한국정보컨버전스학회:학술대회논문집
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• 2008.06a
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• pp.199-204
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• 2008

Sensor nodes have various energy and computational constraints because of their inexpensive nature and ad-hoc method of deployment. Considerable research has been focused at overcoming these deficiencies through faster media accessing, more energy efficient routing, localization algorithms and system design. Our research attempts to provide a method of improvement MAC performance in these issues. We show that traditional carrier-sense multiple access(CSMA) protocols like IEEE 802.11 do not handle the first constraint adequately, and do not take advantage of the second property, leading to degraded latency and throughput as the network scales in size, We present more efficient method of a medium access for real-time wireless sensor networks. Proposed MAC protocol is a randomized CSMA protocol, but unlike previous legacy protocols, does not use a time-varying contention window from which a node randomly picks a transmission slot. To reduce the latency for the delivery of event reports, it carefully decides a fixed-size contention window, non-uniform probability distribution of transmitting in each slot within the window. We show that it can offer up to several times latency reduction compared to legacy of IEEE 802.11 as the size of the sensor network scales up to 256 nodes using widely used simulator ns-2. We, finally show that proposed MAC scheme comes close to meeting bounds on the best latency achievable by a decentralized CSMA-based MAC protocol for real-time wireless sensor networks which is sensitive to latency.