• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.4A
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• pp.579-585
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• 2000

This paper analyzes and compares the blocking performance of all-optical wavelength-routed networks providing circuit switching among users. A connection between two nodes along a particular path must use a single wavelength on all hops, or links, within the path. We then calculate the blocking probability along a lightpath with wavelength conversion in a network with an arbitrary topology and show the network performance improvement offered by node with limited translation technology. We also propose a new schematic method for the performance analysis of different types of network architecture which is composed of nodes with or without wavelength conversion(NC, FC or LC).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.10A
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• pp.929-934
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• 2006

A scheme to easily upgrade TDM-PON using WDM overlay is proposed. To maintain the colorless characteristics of ONU transmitters, a wavelength-conversion ONU is adopted for each TDM-PON group, where all upstream signals from regular ONUs are adjusted to an assigned wavelength. An implementation scheme for remote node and wavelength conversion node is suggested and the test results are shown.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.40-42
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• 2004

본 논문에서는 WDM 네트워크에서 보다 현실적인 파장 변환을 고려하면서 잔여링크를 최대화시킬 수 있는 파장 할당 알고리즘을 제시한다. 기존의 기법들은 각 노드들의 과장 변환 능력을 무시하고 전체 네트워크의 파장 변환 능력을 일률적으로 고정시킨 것을 가정하기 때문에 비효율적이라 할 수 있다. 제안된 기법은 각 노드의 파장 변환 능력을 각각 고려하면서 사용 가능한 잔여링크의 집합을 가능한 최대화 할 수 링(Ring)의 형태로 만든다. 이것은 잔여링크를 최대화하여 어떤 경로 요구가 있더라도 파장을 할당 할 수 있게 한다. 그렇기 때문에 네트워크에서의 블러킹 확률을 최대 19%까지 낮출 수 있었으며, 파장변환 횟수에서 대략 40%의 성능 향상을 보이고, 네트워크의 활용성을 높일 수 있음을 성능 비교를 통해서 볼 수 있다.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.11_12
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• pp.646-653
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• 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 KIISE:Computer Systems and Theory
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• v.28 no.7
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• pp.341-349
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• 2001

본 논문은 N개의 노드로 구성된 파장분할다중화(Wavelength Division Multiplexing) 방식의 Passive Star형 광상호연결망에서 K개의 파장이 사용가능 할 때 패킷 전송 스케쥴링 문제를 다루고 있다. 모든 노드는 파장조율이 가능한 송신기와 특정 파장에 고정된 수신기를 각각 한 개씩 가지고 있으며, 하나의 패킷이 송신기로부터 수신기까지 전송되는 데에 걸리는 시간은 항상 일정하다고 가정한다. 최적의 패킷 전송 스케쥴이란 송신노드 입장에서 임의의 파장에서 다른 파장으로 송신기를 조율하는 데에 따른 지연시간(turning delay)을 고려하여 같은 시간에 최대한 많은 서로 다른 파장을 사용하도록 함과 동시에, 수신노드의 입장에서 수신된 패킷들의 광/전 변환에 따른 지연시간(conversion delay)을 고려하여 패킷의 수신간격을 일정하게 유지함으로써 모든 패킷이 최소시간 내에 전송될 수 있도록 언제 어떤 파장을 사용하여 패킷들을 전송할 것인지 결정하는 것을 말한다. 본 논문에서는 파장조율에 따른 지연시간을 $\delta$로 나타낼 때 모든 노드가 자기 자신을 제외한 다른 모든 노드에 주기적으로 전방송(all-to-all broadcast)을 반복하는 경우에 임의로 주어진 N, K, $\delta$의 값에 대하여 최적의 패킷 전송 스케쥴을 구할 수 있는 알고리즘을 제안하고 있다. 또한, N이 K로 나누어 떨어지면 최적의 전방송 주기는 [NK($\delta$+1)/{$N_2$-N-NK+K$^2$+K}](N-1)임을 증명하였다.

• Journal of the Korea Society of Computer and Information
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• v.10 no.5 s.37
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• pp.123-132
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• 2005

In this Paper, we present an improvement of switch node for wavelength multiplex optical network. Currently because of quick increase of internet traffic a big network capacity is demanded. Wavelength multiplex optical network Provides the data transfer of high speed and the transparent characteristic of the data. Therefore optic network configuration is the most powerful technology in the future. It will be able to control the massive traffic from the optical network in order to transmit the multimedia information of very many quantify. Consequently the node where the traffic control is Possible, is demanded. The optical switch node which manages efficiently the multiple wavelength was Proposed. This switch is composed of a optical switch module for switching and a wavelength converter module for wavelength conversion. It will be able to compose the switch fabric without optical/electro or electro/optical conversion using optical MEMS(Micro Electro Mechanical Switches) module. Finally, we present the good test result regarding the operational qualify of the switch fabric and the performance of optical signal from the switch node. The proposed switch node of the optic network will be able to control the massive traffic with all optical.

• The Journal of Korean Association of Computer Education
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• v.9 no.1
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• pp.97-106
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• 2006

In the next-generation Internet backbone network, DWDM technology was appeared as an alternative to solve circuit shortage of existing TDM-based Internet. In this DWDM Network, it is inevitable to consider wavelength-conversion function as well as RWA in case of setting up connection for the efficient use of resources and customer satisfaction. This study is to describe an efficient strategy for the wavelength-conversion function with a limited range and for the use of a wavelength converter with the selected node, and to verify the optimum use of a wavelength converter through the performance test.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.771-773
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• 1999

본 논문에서는 파장분할다중화 방식을 사용하는 광상호연결망에서 송신기의 지연시간과 수신노드에서의 광/전(光/電) 시간을 동시에 고려하여 각 노드의 패킷 수신 간격이 일정하면서도 전체 방송 주기를 최적화 할 수 있는 송수신 스케쥴링 알고리즘을 제안하고자 한다. 즉, Nro의 노드로 구성된 스타(star)형 구조에서 K개의 파장을 사용하여 일정한 간격으로 패킷을 수신할 경우에 최적의 방송주기를 제시하고 그에 따른 스케쥴링 알고리즘을 설명하고 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.4B
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• pp.394-402
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• 2009

In this paper, we present a new analytical model for estimating the blocking performance of multi-fiber WDM networt:s with sparse and limited wavelength conversion (SLWC). The proposed model is a reduced-load approximation model that can obtain accurate estimates of blocking probability of such networks. Our model employs three new recurrence formulae to obtain the free wavelength distribution on a multi-fiber link, the free wavelength distribution after limited-range wavelength conversion and the end-to-end blocking probability of a multi-hop path, respectively. From the numerical results on the NSFNET, we demonstrate that the blocking performance of two-fiber NSFNET with three wavelength-convertible nodes, each of which translates an input wavelength to its adjacent output wavelengths, closely approximates the blocking performance of full wavelength conversion.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.8
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• pp.1883-1892
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• 1998

This paper considers the efficient design of routing path and wavelength assignment asignment in the sigle-hop WDM optical transport networks. The connecton demands between node-pairs are given and a connection must be made by only one lightpath. It is assumed that no wavelength conversion is allowed and the physical topology of the network is given. This paper proposes a method to find the routes of lightpaths and assign wavelengths to the routes, which minimizes the number of total wavelength to satisfy all connection demands. We establish a new optimization model that finds the minimum number of wavelengths. A heuristic algorithm with polynomial iterations is developed for the problem. The algorithm is implemented and applied to the netowrks with real problem size. The results of the application are compared with the commericial optimization solver, GAMS/OSL and Wauters & Demeester [8].