• The Journal of the Korea Contents Association
• /
• v.8 no.1
• /
• pp.160-168
• /
• 2008

We completed a new cluster system based on WDM by proposing virtual topology reconfiguration schemes. The key idea of the proposed scheme Is to construct a set with the longest chains of requests of connecting nodes which need to be assigned a wavelength. All the sets have no common factor, that is, there is no duplicated link among the requests of connecting. After making the set satisfying this condition, we could assign a wavelength to per corresponding set. We could reconfigure a virtual topology with this scheme collectively. we compared our scheme to existing approaches by the OWns simulation tool. As the results, we gained improved performances, reducing 10% of blocking rate and improving 30% of ADM utilization in terms of the blocking probability and the ADM utilization.

• Journal of KIISE:Computer Systems and Theory
• /
• v.32 no.11_12
• /
• pp.646-653
• /
• 2005

This paper proposes that wavelength assignment algorithm maximizes residual links considering more real wavelength conversion in the WDM network. The existing algorithms are inefficient that they ignore wavelength conversion ability in each nodes and fixed uniformly wavelength conversion ability on all nodes. Proposed method makes a ring shape that maximize available residual links considering wavelength conversion ability in each nodes. Maximizing residual links can assign a wavelength for any path require. Then blocking probability is reduced by the maximum 19 percent and wavelength conversion number is improved by about 40 percent. These can be showed in performance evaluation.

• Journal of Korea Society of Industrial Information Systems
• /
• v.11 no.3
• /
• pp.82-89
• /
• 2006

Optical transmission system related to network infra of ubiquitous is a essential bridge technique between metro network and access point. So, it is need to develop this technique. In this paper, we develop 1Gbps SNMP optical transmitter/receiver system based on 1 core ring-type WDM PON. The developed system can reduce number of optic fiber and doesn't need extra transmitter/receiver. Also, this system can extend nodes owing to many node per wavelength, acts rapidly against security cutting, and acts independent of protocols.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.11B
• /
• pp.663-672
• /
• 2007

This paper proposes an algorithm for design of a multiple ring network that can be applied to an arbitrary topology in the WDM optical transport networks. Especially, we suggest an integer linear program(ILP) formulation with the objective of minimizing the total cost of nodes based on the reconfigurable OADM(ROADM) architecture and propose a heuristic algorithm to reduce computational complexity of the exact problem formulation. To evaluate the performance and validity of this scheme, we applied it to an NSFnet topology assuming the dynamic or static traffic condition and compared it with a mesh methodology about capacity of connection requests and the total cost of the nodes.

• Journal of the Institute of Convergence Signal Processing
• /
• v.21 no.4
• /
• pp.162-169
• /
• 2020

In this paper, we attempted a qualitative understanding of mutual injection locking without rigorous mathematics, and analyzed the proposed mutual injection locked light source. Also, a low-cost WDM-PON light source based on mutual injection locking using two unpolarized Fabry-Perot Laser Diodes (F-P LDs), was implemented. The RIN (Relative Intensity Noise) characteristic for the wavelength change of the F-P LD was measured, and when the variable wavelength range was 2.07 nm, it showed a RIN of at least -110 dB/Hz.

• Journal of the Optical Society of Korea
• /
• v.19 no.1
• /
• pp.13-21
• /
• 2015

In recent years energy consumption has become a main concern for network development, due to the exponential increase of network traffic. Potential energy savings can be obtained from a load-adaptive scheme, in which a day can be divided into multiple time periods according to the variation of daily traffic patterns. The energy consumption of the network can be reduced by selectively turning off network components during the time periods with light traffic. However, the time segmentation of daily traffic patterns affects the energy savings when designing multiperiod logical topology in optical wavelength routed networks. In addition, turning network components on or off may increase the overhead of logical topology reconfiguration (LTR). In this paper, we propose two mixed integer linear programming (MILP) models to design the optimal logical topology for multiple periods in IP-over-WDM networks. First, we formulate the time-segmentation problem as an MILP model to optimally determine the boundaries for each period, with the objective to minimize total network energy consumption. Second, another MILP formulation is proposed to minimize both the overall power consumption (PC) and the reconfiguration overhead (RO). The proposed models are evaluated and compared to conventional schemes, in view of PC and RO, through case studies.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.5B
• /
• pp.404-413
• /
• 2003

Optical Internet consists of IP domain and optical (WDM) domain, where the wavelength routing (WR) and optical burst switching (OBS) are the promising switching technologies in the optical domain. In this paper, we perform the simulations on the WR network and the OBS network, and compare their performances. It is verified from our simulations that the OBS network performs better than the WR network when the same network resources are given.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.6B
• /
• pp.523-532
• /
• 2003

GENMET(GEneralized Multihop Network) which is based on Wavelength-Division Multiplexsing(WDM) and can be used in order to construct the next generation lightwave network is a logical(virtual), packet-switched and multihop topology network. GENMET is a regular multihop network which is a generalization of Shuffle network and do Bruijn network As such, it has the advantage of simple routing which is critical in a high speed network Given a physical topology, different logical topologies can be derived for assigning wavelengths to the UserNodes. By appropriately assigning wavelengths, performance of the network, such as mean hop count, maximum throughput and mean packet delay can be improved. In this paper, we propose heuristic algorithms for effectively assigning a limited number of wavelengths to the given UserNodes. The Performance of proposed algorithm is compared with the random assignment and the lower bounds.

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.8S
• /
• pp.2729-2734
• /
• 2000

본 논문에서는 기존의 논문들이 이상적인 소자들을 가정한 데 비해 WDM 망에서 사용되는 광소자들의 손실특성을 분석하여 수식화하고 이를 이용하여 광경로 설정을 하였다. 비어있는 파장이 있을 경우, 이들 후보 경로중에서 일정 기준 SNR을 만족하면서 최적인 경로를 선택하였다. 그 결과, 파장변환기의 입출력 파장간격에 따라 호거절확률에 변화가 있음을 확인했으며 보다 실제적인 망설계의 방법을 제시하였다.

• Proceedings of the Korean Information Science Society Conference
• /
• 2003.10c
• /
• pp.163-165
• /
• 2003

본 논문에서는 논리적인 다중 링 구조에 의한 WDM 통신망 복구 기법을 제안한다. 이 방법은 링 토폴로지의 특성을 이용해 빠르고 간단한 복구 동작을 제공하며, 지역적인 복구를 수행한다. 동시에 다중 링 구성을 통하여 대체 경로의 분산과 공유 정도를 높이고 단위 링크당 예약되어야 하는 예비 광파장의 수를 줄임으로써 전체 통신망 자원 이용의 효율성을 높일 수 있다.