• Journal of the Korea Society of Computer and Information
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• v.15 no.2
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• pp.99-107
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• 2010

SNMP(Simple Network Management Protocol) is most commonly used as a standard protocol for effective network management by supporting the increasing size of the network and the variety of network elements such as router, switch, server and so on. However, SNMP has performance drawbacks of network overhead, processing latency, and the inefficiency in data retrieval. In this paper, we propose two schemes to improve the performance of SNMP; 1) the first scheme to reduce the amount of redundant OID information within a SNMP-GetBulk response message, 2) the second scheme of newly proposed SNMP-GetUpdate message combined with the cache in MNS. Through the analysis with real experiments, we show that our first scheme reduces the network overhead and the second scheme improves the processing latency and the retrieval of SNMP MB tables. And, therefore the scalability of network management can be improved.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1558-1562
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• 2005

This paper describes the design and implementation of a wireless home network system using Home Network Control Protocol (HNCP) called the wireless HNCP home network system. For wireless interfaces of HNCP, IEEE 802.11b and IEEE 802.15.4 standard protocols are considered. With the implementation of the wireless HNCP home network system, a simple analysis about coexistence between IEEE 802.11b and IEEE 802.15.4 is achieved. Through the implemented wireless HNCP home network system and the analytical results about the coexistence between both two different wireless protocols, the feasibility of the wireless HNCP home network system is shown.

• ETRI Journal
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• v.24 no.2
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• pp.69-81
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• 2002

This paper reviews the existing research activities on signaling and control procedures for IP over optical networks. We focus on the IP-centric signaling and control architecture based on the generalized multi-protocol label switching (GMPLS) protocol and analyze various scenarios and technical issues for deploying the IP over an optical network. We analyze the signaling and operations and administration and maintenance requirements for integrating an IP network and an optical network in order to cope with the high bandwidth and poor resource granularity of the optical network, including the optical cross-connect system. On the basis of network architecture and a reference configuration model, we investigate the GMPLS-based control architecture and interconnection model appropriate for controlling IP bandwidth and optical lambda resources. The signaling and control procedure based on GMPLS on optical user-network interface and network-network interface are comparatively investigated to provide the optical lightpath. We also study protection and restoration procedures to protect link failure when it applies to generalized MPLS signaling.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.11
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• pp.5425-5448
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• 2018

Wireless sensor network has been widely used in Internet of Things (IoT) applications to support large and dense networks. As sensor nodes are usually tiny and provided with limited hardware resources, the existing multiple access methods, which involve high computational complexity to preserve the protocol performance, is not available under such a scenario. In this paper, we propose an intelligent Medium Access Control (MAC) protocol selection scheme based on machine learning in wireless sensor networks. We jointly consider the impact of inherent behavior and external environments to deal with the application limitation problem of the single type MAC protocol. This scheme can benefit from the combination of the competitive protocols and non-competitive protocols, and help the network nodes to select the MAC protocol that best suits the current network condition. Extensive simulation results validate our work, and it also proven that the accuracy of the proposed MAC protocol selection strategy is higher than the existing work.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.9
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• pp.17-28
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• 2004

Since the Internet has grown into a large communication infrastructure, the network management system to systematically manage the large number of network components has become an essential part of the Internet. The rapid growth of network size has brought into question the scalability of the existing centralized model, such as SNMP (Simple Network Management Protocol) and CMIP (Common Management Information Protocol). Thus, for efficient network management, researches about mobile agent have also been performed recently. This paper presents analytical models of centralized approach based on SNMP protocol, distributed approach based on mobile agent, and mixed mode to make up for shortcomings of SNMP and mobile agent. We compare the performance of these analytical models based on network management response time. Experiment results show that performance of mobile agent and the mixed mode is less sensitive to the delay in WAN network environment. However, SNMP is more efficient for the simple network environment like LAN.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.4
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• pp.618-636
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• 1997

DQDB(Distributed Queue Dual Bus) protocol, the IEEE 802.6 standard protocol for metropolitan area networks, does not fully take advantage of the capabilities of dual bus architecture. Although fairness in bandwidth distribution among nodes is improved when using so called the bandwidth balancing mechanism, the protocol requires a considerable amount of time to adjust to changes in the network load. Additionally, the bandwidth balancing mechanism leaves a portion of the available bandwidth unused. In a high-speed backbone network, each node may act as a bridge/ router which connects several LANs as well as hosts. However, Because the existence of high speed LANs becomes commonplace, the congestionmay occur on a node because of the limitation on access rate to the backbone network and on available buffer spaces. to release the congestion, it is desirable to install some congestion control algorithm in the node. In this paper, we propose an efficient congestion control mechanism and fair and waster-free MAC protocol for dual bus network. In this protocol, all the buffers in the network can be shared in such a way that the transmission rate of each node can be set proportional to its load. In other words, a heavily loaded node obtains a larger bandwidth to send the sements so tht the congestion can be avoided while the uncongested nodes slow down their transmission rate and store the incoming segments into thier buffers. this implies that the buffers on the network can be shared dynamically. Simulation results show that the proposed probotol significantly reduces the segment queueing delay of a heavily loaded node and segment loss rate when compared with original DQDB. And it enables an attractive high throughput in the backbone network. Because in the proposed protocol, each node does not send a requet by the segment but send a request one time in the meaning of having segments, the frequency of sending requests is very low in the proposed protocol. so the proposed protocol signigificantly reduces the segment queuing dely. and In the proposed protocol, each node uses bandwidth in proportion to its load. so In case of limitation of available buffer spaces, the proposed protocol reduces segment loss rate of a heavily loaded node. Bandwidth balancing DQDB requires the wastage of bandwidth to be fair bandwidth allocation. But the proposed DQDB MAC protocol enables fair bandwidth without wasting bandwidth by using bandwidth one after another among active nodes.

• Journal of information and communication convergence engineering
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• v.16 no.3
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• pp.135-141
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• 2018

Wireless sensor networks (WSN) are composed of a large number of sensor nodes. Battery-powered sensor nodes have limited coverage; therefore, it is more efficient to transmit data via multi-hop communication. The network lifetime is a crucial issue in WSNs and the multi-hop routing protocol should be designed to prolong the network lifetime. Prolonging the network lifetime can be achieved by minimizing the power consumed by the nodes, as well as by balancing the power consumption among the nodes. A power imbalance can reduce the network lifetime even if several nodes have sufficient (battery) power. In this paper, we propose a routing protocol that prolongs the network lifetime by balancing the power consumption among the nodes. To improve the balance of power consumption and improve the network lifetime, the proposed routing scheme adaptively controls the transmission range using a power control according to the residual power in the nodes. We developed a routing simulator to evaluate the performance of the proposed routing protocol. The simulation results show that the proposed routing scheme increases power balancing and improves the network lifetime.

• Journal of Sensor Science and Technology
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• v.19 no.4
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• pp.297-305
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• 2010

A home healthcare system based wireless sensor network, which can continuously monitor and manage the elderly's electrocardiogram(ECG) signal at any space at home without space limit is proposed. The communication coverage of wireless network is expended by multi-hop wireless sensor network. In order to send the elderly's ECG data wirelessly, a small size ECG sensor node was designed to forward the ECG data over multi-hop relay network. The packet acquired by mobile ECG node is transmitted through wireless intermediate nodes to base station for analyzing the packet reception rate. Modified minimum cost forwarding(MMCF) protocol and flooding protocol are designed and implemented to check the transmission efficiency of a packet in a wireless sensor network. The developed MMCF protocol shows an advantage of high reception rate by reduced network traffic.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.118.1-118
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• 2002

Recent trends in internet access to the device network require that information be provided from anywhere in the enterprise. One then needs to integrate both device network protocol and data network protocol to realize Virtual Device Network (VDN). Interoperability between devices and equipments is essential to enhance the quality and the performance of VDN. LonWorks technology is incorporated as device network protocol for interoperability. VDN integrating both device network and data network has varying time delay. Inherent varying time delay of VDN can significantly degrade the reliability of Distributed Control System. This study investigates the transmission characteristics of VDN and s...

• Bulletin of the Korean Institute for Industrial Safety
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• v.2 no.1
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• pp.6-10
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• 2002

Requirements for Distributed Monitoring and Control Networks(DMCN) differ greatly from those of typical data networks. Specifically, my DMCN technology which employs a filedbus protocol is different from IP network protocol TCP/IP. In general, one needs to integrate fieldbus protocol and TCP/IP to realize DMCN over IP network or internet, which can be viewed as Virtual Device Network(VDN). Interoperability between devices and equipments is essential to enhance the quality and the performance of predictive maintenance(PM). This paper suggests a basic framework for VDN using DMCN over IP network and a method to guarantee interoperability between devices and equipments.