• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1475-1482
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• 2009

In ZigBee network, using energy efficiently is necessary because ZigBee node works by battery. To use energy efficiently, it is one of the way to reduce unnecessary network traffic. In this paper, it presents efficient shortcut routing algorithm using depth of destination node in ZigBee network. In traditional tree routing, each node transfers data only to its own parent or child node, which is inefficient way. Efficient shortcut routing algorithm is also based on tree routing. However, we suggests the algorithm with using neighbor table and depth of destination that is able to transfer data to other neighbor node, not only to parent or child node. It minimizes coordinator bottleneck state and unnecessary intermediate routing path which happens in traditional tree routing.

• The Transactions of the Korea Information Processing Society
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• v.4 no.5
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• pp.1308-1318
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• 1997

This paper proposes a new touthind algorithm, the Bandwidth-Delay-Loss based Routing(BDLR) algotithm, which supports the selection of an effcienet routing path by cinsidering the characteristics and QoS requirements of intergarted servies over the Untegrated Serives Packet Network(ISPN), and also compareas it with other touting algorithms by simulating their perfomances on the various combinations of the realtime and non-realtime traffic over the ISPN. The simulation shows that the BDLR algorithm takes great advantages on transmisson dealy, the satisfiability of QoS requirements, and the adapation of traffic envirment over the other routing algorithms priposed for ISPN until now.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.2871-2877
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• 2014

Real-time communication and diversification of multimedia application services using high-capacity data over the Internet demand high speed connection, and real-time and high-speed access internet service such as multimedia make Internet traffic increase rapidly. Meanwhile, QoS (Quality of Service) of internet service is not satisfied. In this situation, ISP (Internet Service Provider) has been required to improve service quality and extend network according to the user's needs. This request includes issue of extending network focused on increasing router and the number of routing table as well as simply extending bandwidth.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1721-1726
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• 2014

The sensor network technology for core technology of ubiquitous computing is in the spotlight recently, the research on sensor network is proceeding actively which is composed many different sensor node. The major traffic patterns of plenty of sensor networks are composed of collecting types of single directional data, which is transmitting packets from several sensor nodes to sink node. One of the important condition for design of sensor node is to extend for network life which is to minimize power-consumption under the limited resources of sensor network. In this paper analysis used routing protocols using the network simulation that was used second level cluster structure to reduce delay and power-consumption of sensor node.

• The Journal of the Korea Contents Association
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• v.8 no.7
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• pp.43-52
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• 2008

The AODV routing algorithm in a mobile ad-hoc networks broadcasts RREQ packet to find a route from a source to a destination. An attacker node may intercept a RREQ packet and attack by falsifying a field in that packet. In this paper, we propose a simply modified method which can protect a routing table from an attack to falsify the hop count field in the RREQ packet. When establishing a connection between a source and a destination, we update routing table of each node on the connection based on minimum delay instead of minimum hop count. By doing this, we can protect routing table from an attack to falsify a hop count Our simulation is implemented in Network Simulator(NS-2). We analyze how an attacker affects the mobile ad-hoc networks. The result of the simulation shows that the proposed mechanism transfers a data securely.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11A
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• pp.1034-1042
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• 2008

It is very hard, but important to sustain path stability for a reliable communication in mobile ad hoc networks. We propose a novel source routing protocol that establishes a group path with virtual multiple paths to enable a robust communication. The entire mobile nodes form a disjoint set of clusters: Each has its clusterhead as a cluster leader and a unique cluster label to identify itself from other clusters. A group path is a sequence of cluster labels instead of nodes and the nodes with the same label collaborate to deliver packets to a node with next label on the group path. We prove by resorting to simulation that our proposed protocol outperforms the existing key routing protocols, even for a network with a high node mobility and a high traffic.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.10
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• pp.859-876
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• 2012

Since the existing protocols separated mobility management part and routing protocol part in their design and used a flooding, they suffer from the high control overhead, thereby limiting performance. In this paper, we use a tree-based mobility management method and present a simple and efficient routing protocol that exploits the topology information which is built additionally through mobility management. Thus, the mobility management and the routing protocol closely cooperate to optimize control overhead. Furthermore, we use a progressive path discovery method to alleviate traffic congestion around IG and a unicast-based broadcast method to increase the reliability of message delivery and to judge link validity promptly. The proposed protocol reduces control overhead greatly and works in a stable manner even with the large number of nodes and high mobility. This was proven by comparing with the AODV protocol that employs the hybrid mobility management protocol.

• Journal of the Korea Society for Simulation
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• v.15 no.1
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• pp.27-33
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• 2006

To guarantee QoS (Quality of Service), routers should determine routing paths satisfying service requirements, based on link state information as well as network topology. Link status database (LSD) in routers should be efficiently managed to effectively reflect the current state of all links. However, there is a trade off between the exact reflection of the current link status and its update cost. For exactly reflecting the current link status, each router immediately notifies its neighbors that link state information is changed. This may degrade performance of the router due to the processing of link state update messages. On the other side, if the current link state information is not updated appropriately, a route setup request can be rejected because of the discrepancy between the current link state information and previously updated link state information in LSD. In this paper, we propose a traffic variation based link state update algorithm for adaptively controlling the generation of link state update messages and compare its performance with those of four existing algorithms by intensive simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.12B
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• pp.1066-1080
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• 2003

In this paper a scalable QoS routing scheme for distributed multimedia applications in a hierarchical wide area network is proposed. The problem of QoS routing is formulated as a multicriteria shortest path problem, known as NP-complete. The proposed hierarchical routing scheme consists of two phases. In Phase 1, every border node periodically pre-computes the QoS distance for the paths between every pair of border nodes in any level of domain hierarchy. This phase is independet of the QoS request from an application. In Phase II, distributed graph construction algorithm is performed to model the network as a graph by retrieving pre-computed QoS distances. The graph is constructed by the on-demand algorithm and contains a part of the network topology which is completely neglected or partially considered by existing routing schemes, thus maintaining more accurate topology information. By using retrieval approach rather than advertising one, no global QoS state information exchange among nodes is needed. In this Phase, distributed partition algorithm for QoS routing problem is also performed, thus eliminating virtual links on the hierarchically complete path.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4B
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• pp.162-169
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• 2005

Network traffic measurements show that the data traffic on packet switched networks has the self-similar features which is different from the traditional traffic models such as Poisson distribution or Markovian process model. Most of the call admission control researches have been done on the performance analysis of a single network switch. It is necessary to consider the performance analysis of the proposed admission control scheme under interconnected switch environment because the data traffic transmits through switches in networks. From the simulation results, it is shown that the call admission control scheme may not operate properly on the interconnected switch even though the scheme works well on a single switch. In this parer, we analyze the cell loss probability, utilization and self-similarity of output ports of the interconnected networks switch by using shared buffer memory management schemes and propose the new call admission control scheme considering the interconnected network switches under self-similar traffic environments.