• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.4
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• pp.180-187
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• 2002

Many real-time multimedia applications, such as video conferencing have stringent end-to-end delay constraints and consume large amount of network resources. In order to support these applications efficiently, multicast routing algorithms computing least cost multicast trees that satisfy a given end-to-end delay constraint are needed. However, finding such a tree is known to be computationally expensive. Therefore, we propose a heuristic distributed multicast routing algorithm that reduces a “finding multicast tree”that satisfies a given end-to-end delay constraint and minimizes the average resulting tree cost. Also, simulation results show that the proposed algorithm has much better average cost performance than other existing algorithms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5B
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• pp.508-519
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• 2004

This paper proposed two multi-path constraint-based routing algorithms for Internet traffic engineering using MPLS. In normal constraint-based shortest path first (CSPF) routing algorithm, there is a high probability that it cannot find the required path through networks for a large bandwidth constraint that is one of the most important constraints for traffic engineering, The proposed algorithms can divide the bandwidth constraint into two or more sub-constraints and find a constrained path for each sub-constraint, if there is no single path satisfying the whole constraint. Extensive simulations show that they enhance the success probability of path setup and the utilization of network resources.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.3
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• pp.287-299
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• 2000

In this paper, we classify multicast methods into three categories, i.e., tree-based, path-based, and hybrid-based multicasts, for a multicomputer employing the bidirectional torus network and wormhole routing. We propose the dynamic partition multicast routing (DPMR) as a path-based algorithm. As a hybrid-based algorithm, we suggest the hybrid multicast routing (HMR), which employs the tree-based approach in the first phase of routing and the path-based approach in the second phase. Performance is measured in terms of the average latency for various message length to compare three multicast routing algorithms. We also compare the performance of wormhole routing having variable buffer size with virtual cut-through switching. The message latency for each switching method is compared using the DPMR algorithm to evaluate the buffer size trade-off on the performance.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.2
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• pp.89-95
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• 2002

Global routing is to assign each net to routing regions to accomplish the required interconnections. The most popular algorithms for global routing inlcude maze routing algorithm, line-probe algorithm, shortest path based algorithm, and Steiner tree based algorithm. In this paper we propose weighted network heuristic(WNH) as a minimal Steiner tree search method in a routing graph and a genetic algorithm based on WNH for the global routing. We compare the genetic algorithm(GA) with simulated annealing(SA) by analyzing the results of each implementation.

• Journal of KIISE:Information Networking
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• v.37 no.5
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• pp.374-385
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• 2010

Wireless mesh networks can be deployed for various networks from home networking to last-mile broadband Internet access. Wireless mesh networks are composed of mesh routers and mesh clients. In these networks, static nodes form a multi-hop backbone of a large wireless access network that provides connectivity to end-users' mobile terminals. The network nodes cooperate with each other to relay data traffic to its destinations. In order to increase connectivity and better performance, researchers are getting interested in multi-channel and multi-interface wireless mesh networks. In these networks, non-overlapping multiple frequency channels are used simultaneously to increase the aggregate bandwidth available to end-users. Recently, researches have focused on finding suitable channel assignments for wireless network interfaces, equiped in a mesh node, together with efficient routing to improve overall system throughput in wireless mesh networks. This goal can be achieved by minimize channel interference. Less interference among using channels in a network guarantees more aggregated channel capacity and better connectivity of the networks. In this thesis, we propose interference aware channel assignment and routing algorithms for multi-channel multi-hop wireless mesh networks. We propose Channel Assignment and Routing algorithms using Traffic Profiles(CARTP) and Routing algorithms allowing detour routing(CARTP+2). Finally, we evaluate the performance of proposed algorithms in comparison to results from previous methods using ns-2 simulations. The simulation results show that our proposed algorithms can enhance the overall network performance in wireless mesh networks.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.3
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• pp.61-72
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• 2002

In this paper, we propose two timing-driven routing algorithms for single-source net and multi-source net as applications of 1-Steiner heuristic algorithm. Using the method of substituting the cost of 1-Steiner heuristic algorithms with interconnection delay, our routing algorithms can route both single-source net and multi-source net which have all critical source-terminal pairs or one critical pair efficiently Our single-source net routing algorithm reduced the average maximum interconnection delay by up to 2.1% as compared with previous single-source routing algorithm, SERT, and 10.6% as compared with SERT-C. and Our multi-source net routing algorithm increased the average maximum interconnection delay by up to 2.7% as compared with MCMD A-tree, but outperforms it by up to average 1.4% when the signal net has only subset of critical node pairs.

• The KIPS Transactions:PartC
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• v.14C no.1 s.111
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• pp.73-80
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• 2007

In conventional on-demand mobile ad hoc routing algorithms, an alternate path is sought only after an active path is broken. It incurs a significant cost in terms of money and time in detecting the disconnection and establishing a new route. In this thesis, we propose proactive route selection and maintenance to conventional mobile ad hoc on-demand routing algorithms. The key idea for this research is to only consider a path break to be likely when the signal power of a received packet drops below an optimal threshold value and to generate a forewarning packet. In other words, if a path is lost with high probability, the neighboring node that may easily be cut off notifies the source node by sending a forewarning packet. Then the source node can initiate route discovery early and switched to a reliable path potentially avoiding the disconnection altogether. For the simulational study, network simulator(NS2) is used. The result of simulation shows that the algorithm significantly improves the performance of networks comparing to conventional on-demand routing protocols based on DSR and AODV in terms of packet delivery ratio, packet latency and routing overhead.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.3
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• pp.63-69
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• 2002

Detailed routing is a problem assigning each net to a track after global routing. The most popular algorithms for detailed routing include left-edge algorithm, dogleg algorithm, and greedy channel routing algorithm. In this paper we propose a genetic algorithm searching solution space for the detailed routing problem. We compare the performance of proposed genetic algorithm(GA) for detailed routing with that of greedy channel routing algorithm by analyzing the results of each implementation.

• Proceedings of the Korean Society of Computer Information Conference
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• 2012.01a
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• pp.105-108
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• 2012

Wireless mesh networks are considered a promising solution to last mile broadband. The unique characteristics of WMN impose unique requirements on designing routing protocols and metrics for WMN. However, existing routing schemes that are designed for single-channel multi-hop wireless networks may lead to inefficient routing paths in multichannel. This paper focuses on the routing problem for multi-radio multichannel WMNs. We list the challenges in designing routing algorithms for multi-radio multichannel WMNs. Then we examine the requirements and considerations for designing routing metrics according to the characteristics of multi-radio multichannel WMNs. Finally we survey and investigate the existing routing metrics in terms of their ability to satisfy these requirements.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.5
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• pp.1-9
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• 1993

In this paper, we develop enhanced hypercube architectures and routing algorithms to realize arbitrary permutations in circuit switching. We prove that a hypercube is rearrangeable if one additional pair of links (one full-duplex communication line) is provided in only one dimesion of connections. We also prove that if each connection between two neighboring nodes consists of two pairs of links, the hypercube can handle two independent permutations simultaneously.