• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.25 no.9A
• /
• pp.1395-1404
• /
• 2000

In this paper, we propose a heuristic wavelength routing algorithm for IP datagrams in WDM (Wavelength-Division Multiplexing) networks which operates in a distributed manner, while most previous works have focused centralized algorithms. We first present an efficient construction method for a loose virtual topology with a connectivity property, which reserves a few wavelength to cope with dynamic traffic demands properly. This connectivity property assures that data from any source node could reach any destination node by hopping one or multiple lightpaths. We then develop a high-speed distributed wavelength routing algorithm adaptive to dynamic traffic demands by using such a loose virtual topology and derive the general bounds on average utilization in the distributed wavelength routing algorithms. Finally, we show that the performance of the proposed algorithms is better than that of the FSP(Fixed Shortest-Path) wavelength routing algorithms through simulation using the NSFNET[1] and a dynamic hot-spot traffic model, and that the algorithms is a good candidate in distributed WDM networks in terms of the blocking performance, the control traffic overhead, and the computation complexity.

• 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.

• Proceedings of the Korean Information Science Society Conference
• /
• 2000.04a
• /
• pp.686-688
• /
• 2000

본 논문에서는 광 네트워크에서 파장(Wavelength)의 라우팅(Routing)문제와 파장할당 (Wavelength Assignment)문제 해결에 필요한 파장의 개수를 찾아내는데 있어서 Ants System의 적용이 기존의 다른 방법과 유사하거나 일부 더 좋은 결과를 나타냄을 보인다. 또한, 광 네트워크에서 각 링크가 균등하게 사용되도록 함으로써 광경로(lightpath)의 개수를 최소화하여, 주어진 네트워크에서의 파장의 최소 개수를 찾아내는데 Ants System이 효과적으로 적용될 수 있음을 보인다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.4
• /
• pp.2382-2392
• /
• 2014

In this paper, a new data frame structure for wavelength routing in optical ring access network(ORAN) is designed and the functions of each field in the frame are defined. In addition, the IP packet transmission to the network layer corresponding to the newly proposed structure of the protocol stack is newly presented. Tha data transmission protocol design techniques of ORAN was proposed. IP packet and broadcasting packet transmission within the sub-network, and the IP packet transmission to other sub-network was shown through the process illustration. In the process, the encapsulation and framing process of the wavelength information to routing has been described in detail. And each step takes place in a packet transfer process is demonstrated. A ring type optical access network protocol is not yet research field. ORAN data transfer protocol to send/receive module structure of a subscriber node and a control node of the two rings which analyzed the results are shown. The high-speed Internet solution is proposed that by using wavelength routing the packet transport protocol for ORAN is designed.

• Proceedings of the Optical Society of Korea Conference
• /
• 2001.02a
• /
• pp.170-171
• /
• 2001

차세대 광 인터넷 시스템을 구축하는 데 있어서 패킷을 광신호 상태에서 라우팅하기 위한 전광 교환 방식에 대한 연구가 최근 관심을 끌고 있다. 전광 패킷 라우팅모듈을 구현하는 데 있어서 파장변환 기술은 필수적이며 여러 가지 형태에 대한 연구개발이 진행되고 있다. 최근에는 반도체 광 증폭기로 형성된 방향성 결합기 구조(semiconductor optical amplifier directional coupler)에서의 상호위상변조(XPM ： cross-phase modulation)에 의한 파장변환에 대한 개념이 제안되고 가능성이 실험적으로 입증된 바 있다. (중략)

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.40 no.10
• /
• pp.1-7
• /
• 2003

In this paper, we propose load balanced routing and wavelength assignment (RWA) algorithm for static model. The proposed algorithm arranges the routing paths over the link uniformly and assigns routing paths according to the length of routing paths orderly. Thus, the proposed algorithm can efficiently utilize the network resources. Through the computer simulation on layered-graph model, we prove that the proposed algorithm improves network throughput and reduces blocking probability comparing to first-fit algorithm [1］. Moreover, the proposed algorithm considerably reduces computational time.

• Journal of Korea Multimedia Society
• /
• v.14 no.1
• /
• pp.33-43
• /
• 2011

Routing technologies considering QoS-based hypermedia services have been seen as a crucial network property in next generation optical Internet (NGOI) networks based on IP/dense-wavelength division multiplexing (DWDM). The huge potential capacity of one single fiber. which is in Tb/s range, can be exploited by applying DWDM technology which transfers multiple data streams (classified and aggregated IP traffics) on multiple wavelengths (classified with QoS-based) simultaneously. So, DWDM-based optical networks have been a favorable approach for the next generation optical backbone networks. Finding a qualified path meeting the multiple constraints is a multi-constraint optimization problem, which has been proven to be NP-complete and cannot be solved by a simple algorithm. The majority of previous works in DWDM networks has viewed heuristic QoS routing algorithms (as an extension of the current Internet routing paradigm) which are very complex and cause the operational and implementation overheads. This aspect will be more pronounced when the network is unstable or when the size of network is large. In this paper, we propose a flooding-based unicast and multicast QoS routing methodologies(YS-QUR and YS-QMR) which incur much lower message overhead yet yields a good connection establishment success rate. The simulation results demonstrate that the YS-QUR and YS-QMR algorithms are superior to the previous routing algorithms.

• Proceedings of the Optical Society of Korea Conference
• /
• 2003.07a
• /
• pp.16-17
• /
• 2003

지난 수년간 인터넷 보급에 따른 급격한 통신량 증가에 따른 요구는 차세대 통신 기술인 WDM을 구축하게 되었고 이에 따라 WDM 라우팅 기술과 스위칭 기술이 절실히 필요로 하게 되었다. WDM에 있어서 다른 경로나 목적지로 신호를 보내기 위해서는 신호의 파장이 변환 되어야 하므로 신호의 파장변환은 라우팅에 있어 핵심적인 기술 중 하나로 인식되어지고 있다 현재 사용되어지고 있는 전광 파장 변환기는 주로 SOA (Semiconductor Optical Amplifier)의 비선형 특성인 XGM, XPM, FWM등을 이용한 것으로서 편광 민감성, ASE에 의한 SNR 감소, 신호크기 변형과 높은 가격으로 인해 안정적인 파장변환기로 쓰기에는 다소 무리가 있다. (중략)

• Journal of Korea Multimedia Society
• /
• v.14 no.5
• /
• pp.658-668
• /
• 2011

Over the past decade, the improvement of communications technologies and the rapid spread of www (World Wide Web) have brought on the exponential growth of users using Internet and real time multimedia multicast services like video conferencing, tele-immersive virtual reality, and Internet games. The dense-wavelength division multiplexing (DWDM) networks have been widely accepted as a promising approach to meet the ever-increasing bandwidth demands of Internet users, especially in next generation Internet backbone networks for nation-wide or global coverage. A major challenge in the next generation Internet backbone networks based on DWDM technologies is the resolution of the multicasting RWA (Routing and Wavelength Assignment) problem; given a set of wavelengths in the DWDM network, we set up light-paths by routing and assigning a wavelength for each connection so that the multicast connections are set-upped as many as possible. Finding such optimal multicast connections has been proven to be Non-deterministic Polynomial-time-complete. In this paper, we suggest a new heuristic multicast routing and wavelength assignment method for multicast sessions called DVS-PMIPMR (Differentiated Virtual Source-based Priority Minimum Interference Path Multicast Routing algorithm). We measured the performance of the proposed algorithm in terms of number of wavelength and wavelength channel. The simulation results demonstrate that DVS-PMIPMR algorithm is superior to previous multicast routing algorithms.

• Journal of KIISE:Information Networking
• /
• v.36 no.4
• /
• pp.286-296
• /
• 2009

A major challenge in next generation optical Internet (NGOI) networks based on dense-wavelength division multiplexing (DWDM) is the provision of guaranteed quality-of-service (QoS) for a wide variety of multimedia applications. One of the critical issues in NGOI is the routing and wavelength assignment problem that is embossed as very important and plays a key role in improving the global efficiency for capacity utilization. But the previous researches had the delay problem, and the path routed by higher priority nodes may be congested and interfere with potential future multicast session requests. To overcome these problems, in this research we suggest a Priority-based Minimum Interference Path Multicast Routing (PMIPMR) algorithm, a new routing algorithm which finds alternative routes based on node priorities and Virtual Source (VS) nodes that has both splitting and wavelength conversion, and then chooses a path that does not interfere with potential future multicast session requests when congestions occur in the network. The PMIPMR algorithm reduces blocking rate significantly and increases the wavelength utilization by avoiding congestion in future multicast session requests.