• ETRI Journal
• /
• 제30권2호
• /
• pp.216-226
• /
• 2008

This paper proposes a novel transport network architecture for the next generation network (NGN) based on the optical burst switching technology. The proposed architecture aims to provide efficient delivery of various types of network traffic by satisfying their quality-of-service constraints. To this end, we have developed a soft-state bandwidth reservation mechanism, which enables NGN transport nodes to dynamically reserve bandwidth needed for active data burst flows. The performance of the proposed mechanism is evaluated by means of numerical analysis and NS2 simulation. Our results show that the packet delay is kept within the constraint for each traffic flow and the burst loss rate is remarkably improved.

• 한국통신학회논문지
• /
• 제16권4호
• /
• pp.326-334
• /
• 1991

자유공간 광학과 출력 버퍼 메모리를 이용한 Optical Asynchronous Transfer Mode(ATM) 스위칭 시스템을 제안하고, Huygens-Fresnel 원리와 렌즈 변환을 이용하여 이 스위칭 구조에 있는 분배 시스템을 분석했다. 단색관 조명의 경우, 입력 분포의푸리에 변환과 유사한 패턴이 출력평면에서 관측되었다. 부분적으로 코히런트(coherent)한 유사 단색광으로 시스템을 조명할 \ulcorner\ulcorner는, 출력평면에서 단색광 때보다 공간적으로 넓어진 빛의 세기 분포가 나타났다. 100fs 정도의 코히런트(coherent)한 단펄스는 심한 공간적 확장 없이 분배기를 전파할 수 있음을 알 수 있었다.

• 한국멀티미디어학회논문지
• /
• 제16권9호
• /
• pp.1067-1076
• /
• 2013

Known as an important criterion that evaluates performance of future high-speed backbone networks, burst data loss ratio is well-studied in Optical Burst Switching networks. Current literatures mostly focus on reduce burst loss ratio without considering the system stability and link utilization after reducing. In this paper, we propose a novel framework which comes from feedback theoretic to dynamically control burst loss ratio in OBS. The proposed scheme tries to track the pre-set values of burst loss ratio and increases the stability and link utilization degree. The simulation results show that measured burst loss ratio always tracks setup reference with small errors, wavelength channel utilization is increased up to 2% and the system stability is also improved.

• Journal of Communications and Networks
• /
• 제9권4호
• /
• pp.377-382
• /
• 2007

This paper presents a new enhanced dynamic and multilayer protection(DMP) routing scheme that considers cooperation between packet and wavelength switching domain in order to minimize the resource consumption. The paper describes the architecture of the multilayer network scenario and compares the proposed algorithm with other routing mechanisms applying protection at the IP/multi-protocol label switching(MPLS) layer or at the optical layer. Simulation results show that DMP reduces the number of optical-electrical-optical(o-e-o) operations and makes an efficient use of the network resources compared to non-multilayer proposals.

• Journal of Electrical Engineering and Technology
• /
• 제2권2호
• /
• pp.263-266
• /
• 2007

We report a nickel optical MEMS switch, being able to rotate through a large angle and to accommodate multiple channels. The proposed optical switch consists of a thin nickel mirror and two torsion springs supporting the mirror. The torsion springs are designed using a finite element method (FEM) such that plastic deformation of the thin nickel is avoided during the large torsion actuation. For switching speed improvement, transient vibration of the released mirror is suppressed by optimizing the mirror design and a fast switching response of $200\;{\mu}s\;(pull-down)/300\;{\mu}s\;(pull-up)$ is demonstrated.

• ETRI Journal
• /
• 제44권2호
• /
• pp.274-285
• /
• 2022

Retransmission in optical burst switching networks is a solution to recover data loss by retransmitting the dropped burst. The ingress node temporarily stores a copy of the complete burst and sends it each time it receives a retransmission request from the core node. Some retransmission schemes have been suggested, but uncontrolled retransmission often increases the network load, consumes more bandwidth, and consequently, increases the probability of contention. Controlled retransmission is therefore essential. This paper proposes a new controlled retransmission scheme for loss recovery, where the available bandwidth of wavelength channels and the burst lifetime are referred to as network conditions to determine whether to transmit a dropped burst. A retrial queue-based analysis model is also constructed to validate the proposed retransmission scheme. The simulation and analysis results show that the controlled retransmission scheme is more efficient than the previously suggested schemes regarding byte loss probability, successful retransmission rate, and network throughput.

• 한국광학회:학술대회논문집
• /
• 한국광학회 2005년도 제16회 정기총회 및 동계학술발표회
• /
• pp.284-285
• /
• 2005

• 한국광학회:학술대회논문집
• /
• 한국광학회 2002년도 제13회 정기총회 및 2002년도 동계학술발표회
• /
• pp.164-165
• /
• 2002

• 한국광학회:학술대회논문집
• /
• 한국광학회 1999년도 제16회 광학 및 양자전자 학술발표회Proceedings of 16th Optics and Quantum Electronics Conference, 1999
• /
• pp.206-207
• /
• 1999

• 한국광학회:학술대회논문집
• /
• 한국광학회 1996년도 Advance Program of 13th optics andquantum Electronics conference, 1996제13 회 광학 및 양자전자 학술 발표회 논문 요약집
• /
• pp.107-107
• /
• 1996