• International journal of advanced smart convergence
• /
• v.8 no.1
• /
• pp.35-43
• /
• 2019

A metro ring network using WDM technology requires many issues to be considered even though its transmission distance is shorter and its transmission capacity is lower than a long-haul WDM system. Unlike a long-haul WDM system, which is basically point-to-point configuration, a metro ring network usually equips with capabilty of wavelength reconfiguration. Therefore network performance considering crosstalk within OADM and the network behavior when the ring network is closed should be analyzed before implemented. We discussed some of results analyzed for the issues. Furthermore we proposed a novel method to design a dispersion map for a ring network, and demonstrated the methodology with an exemplary 8-node ring network of 399km circumference.

• Journal of IKEEE
• /
• v.15 no.2
• /
• pp.157-163
• /
• 2011

In this paper, novel traffic groomming algorithms are proposed with a primary goal for maximizing throughput in WDM Multi-ring networks. To achieve this goal, we design four network topologys that are ITG, STG, MTG, PMTG and simulate the throughput in uniform traffic environments. From this methods, we proposed novel traffic groomming algorithms to maximize throughput in WDM Multi-ring networks.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.25 no.6A
• /
• pp.813-817
• /
• 2000

A bidirectional 4-fiber path switched WDM ring is proposed, which provides 1:1 system protection for a digital client layer such as SONET system. It can provide better optical SNR than usual bidirectional line switched ring. Two implementation schemes are proposed and especially, a distributed control scheme is found to be feasible in simple structure with good performance even without supervisory channel.

• Proceedings of the IEEK Conference
• /
• 1999.06a
• /
• pp.154-157
• /
• 1999

Photonic Slot Routing(PSR) is a promising approach to solve the fundamental scalability problem of all-optical packet switched WDM networks. In photonic slot routing, packets destined for the same subnetwork are aggregated to form a photonic slot which is jointly routed as a single unit of information through the network. The relative location of the nodes from bridge may cause to fairness problem in the unidirectional WDM ring network based on PSR. As photonic slots from different subnetworks can originate contentions at the bridge, packets may be dropped and retransmitted. Thus we evaluated the performance of PSR based WDM ring network in the point of fairness for each node and slot contentions at the bridge. Simulation results show that the PSR based WDM ring requires a slot access mechanism to guarantee the transmission fairness and efficient switch architecture to resolve slot contention at the bridge.

• Korean Management Science Review
• /
• v.26 no.3
• /
• pp.1-9
• /
• 2009

In this paper, we present mathematical models for the ring covering problems arising in the design of multi-ring WDM networks. Also, we present efficient algorithms to solve the suggested models. By the computational experiment, our model can solve the medium-sized networks efficiently and shows better performance than the existing heuristic method. Although we propose an efficient method for the column generation procedure, branching rule that does not destroy the column generation structure is unsolved. Further research is required to develop an effective branching rule.

• Journal of Korean Institute of Industrial Engineers
• /
• v.30 no.3
• /
• pp.213-223
• /
• 2004

We consider the traffic grooming problem for the design of SONET/WDM(Synchronous Optical NETwork/Wavelength Division Multiplexing) ring networks. Given a physical network with ring topology and a set of traffic demands between pairs of nodes, we are to obtain a stack of rings with the objective of minimizing the number of ADMs installed at the nodes. This problem arises when a single ring capacity is not large enough to accommodate all the demands. As a solution method, an efficient algorithm based on the branch-and-price approach has been reported in the literature for the problem in which only unidirecional path switched ring (UPSR) was considered. In this study, we suggest integer programming models and the algorithms based on the same approach as the above one, considering two-fiber bidirectional line switched ring(BLSR/2), and BLSR/4 additionally. Using the results, we compare the number of required ADMs for all types of the ring architecture.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1999.04a
• /
• pp.381-383
• /
• 1999

WDM(Wavelength Division Multiplexing) Ring에서 경로과 고정된 파장할당문제는 Circular Arc Graph(CAG)에서의 vertex coloring문제와 동일하다. 본 연구에서는 극대독립집합(Maximal Independent Set)으로 vertex를 cover하는 정수계획법 모형을 제시하고 이를 효율적으로 풀 수 있는 column generation approach와 실험결과를 제시하겠다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.6B
• /
• pp.645-651
• /
• 2002

This thesis describes two wavelength allocation algorithms applied to OMS (Optical Multiplex Section) or OCh (Optical Channel) SPRING (Shared Protection Ring) and compares their characteristics by simulations. Two wavelength allocation algorithms are optimal algorithm and nonblocking algorithm applicable on SPRING WDM networks. In particular, when a node is added in previous ring network, how to work for each algorithm is considered. The optimal algorithm is better than nonblocking for most of comparisons. Nonblocking algorithm has an important advantage, though. Nonblocking algorithm has no wavelength connection or allocation to reconfigure some previous connections.

• Journal of Korea Society of Industrial Information Systems
• /
• v.12 no.4
• /
• pp.148-152
• /
• 2007

This paper develops an integrated optic transmitter/receiver based on ring-type WDM PON. The optic transmitter/receiver can transmit real-time images from the CCTV of a remote street without compression and transmit TCP/IP data using an optic fiber. This system can also perform remote controls of the CCTV camera. The developed optic transmitter/receiver can provide the monitoring service of an advanced image quality of remote traffic using a broadband technology.

• Proceedings of the IEEK Conference
• /
• 1999.06a
• /
• pp.17-20
• /
• 1999

In these days, wavelength division multiplexing(WDM) all-optical network are being deployed to support various multimedia communication services. In this paper, various WDM all-optical network are discussed, and a design of an all-optical backbone network has been proposed by using multiple self-healing ring technology. The proposed multiple self-healing ring network improves network expandability and efficiency of bandwidth, while it retains simplicity and ease of network control, which are from the nature self-healing ring. Using PDI traffic modeling technique, a well-balanced all-optical backbone network using multiple self-healing ring is designed for the 2010s in Korea.