• Journal of Digital Convergence
• /
• v.20 no.4
• /
• pp.459-468
• /
• 2022

In medical area, very high resolution images, which is loss sensitive data, are used. Therefore, the use of optical internet with high bandwidth and the transmission of high realiability is required. However, according to the nature of the Internet, various data use the same bandwidth and a new scheme is needed to differentiate effectively these data. In order to achieve the differentiation, optical delay line buffers are used. However, these buffers is constructed based on some optimal values such as the average offered load, measured data burst length, and basic delay unit. Once the buffers are installed, they are impossible to reinstall new buffers. So, the scheme changing burst length dynamically was considered. However, this method is highly unstable. Therefore, in this article, in order to guarantee the stable operation of the scheme, the analysis of operation conditions is performed. With the analysis together with the scheme, high resolution medical data with the higher class can transmit stably without loss.

• Journal of Digital Convergence
• /
• v.20 no.3
• /
• pp.377-388
• /
• 2022

Various researches are actively studied to satisfy exponentially increasing the usage of the Internet as well as the diverse service demands. Especially the Optical Internet that delivers several Tbps through a single optical fiber requires the intelligence to satisfy the various types of survivability requirements. In the paper, a novel recovery scheme that satisfies the various restoration demands in IP over WDM networks is proposed. The scheme classifies the restoration services into three classes and applies dedicated protection and shared restoration scheme with different priorities for each class. Also, a configuration scheme for information database to support the scheme is proposed. This scheme satisfies the different degree of restoration demands in terms of restoration time, blocking rate and resource usage. With the scheme, medical data can be transmitted without loss.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.10C
• /
• pp.937-944
• /
• 2002

The current fast-growing Internet traffic is demanding more and more network capacity. Photonic packet switching offers high-speed, data rate/format transparency, and configurability, which are some of the important characteristics needed in future networks supporting different forms of data. In this paper, we define that optical backbone networks for IP transport consist of optical packet core switches and optical fibers. We propose a multi-link photonic packet switch managing as single media which unifies the whole bandwidth of multiple wavelengths on the optical fiber in the WDM optical networks. The proposed switch uses optical packet memories of output link equally as well as using the WDM buffer. So it cuts down the required number of buffers and realizes of the optical packet memory economically.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2003.11a
• /
• pp.453-456
• /
• 2003

DWDM(Dense Wavelength Division Multiplexing) 기반의 광 네트워크가 범 세계적인 차세대 광 인터넷(NGOI: Next Generation Optical Internet) 백본망의 대안으로 인식되고 있으나, 기존의 전기적인 오버헤드 비트를 이용한 전송 관리 정보의 사용이 더 이상 유효하지 않아 장애 관리에 많은 문제점을 드러내고 있다. 본 논문에서는 NGOI 백본망의 링크 관리를 위해 광 성능 모니터링 시스템 및. GMPLS(Generalized Multi-Protocol Label Switching)의 링크 관리 프로토콜(LMP: Link Management Protocol)을 활용한 관리 모델을 제시한다.

• Journal of Communications and Networks
• /
• v.9 no.4
• /
• pp.368-376
• /
• 2007

The large potential bandwidth available in wavelength-division multiplexed optical networks makes this technology of crucial importance for satisfying the ever increasing capacity requirements of the next-generation Internet. In this scenario, the routing and wavelength assignment(RWA) problem that concerns determining the optical paths and wavelengths to be used for connection establishment in a wavelength-routed network, is still one of the most important open issues. In this paper we propose a new online dynamic grooming-capable RWA heuristic scheme working on wavelength division multiplexing(WDM) networks as a multistage selection process. The proposed algorithm is transparent with respect to the presence of wavelength converters, achieves very low connection rejection ratios with minimal computational complexity and is appropriate for the modern multilayer optical circuit and wavelength switched networks with sparse wavelength conversion capability.

• International journal of advanced smart convergence
• /
• v.13 no.3
• /
• pp.48-58
• /
• 2024

Fiber to the Home (FTTH) technology is among the most advanced broadband services, delivering voice, data, and television through a single optical fiber directly to customer premises, ensuring high-speed and reliable connectivity. The study conducted on Nepal Telecom's FTTH networks involved direct measurements from the optical line terminal to the fiber access point and optical network unit, providing detailed insights into network performance. Using the OptiSystem software, the analysis revealed a link loss of 24.99 dB, a Q-factor of 12.98, and a minimum Bit Error Rate (BER) of 7.31E-39, all within standard limits, which underscores the robustness of the network. The study also identified that the highest contributors to signal loss were connector loss, fiber attenuation, and fusion splices, emphasizing the importance of minimizing these factors to maintain optimal network performance. Overall, these findings highlight the critical aspects of FTTH network design and maintenance, ensuring that service providers can deliver high-quality broadband services to customers.

• 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.

• Korean Journal of Optics and Photonics
• /
• v.20 no.5
• /
• pp.261-265
• /
• 2009

Our amplifier using an all optical method and a fixed GFF achieved automatic gain flatness throughput the C-band without any NF degradation, and simultaneously achieved a constant 25 dB gain, while input signals were varied between one channel and forty WDM channels. When thirty nine channels were added and dropped, the transient gain variation of the survival channel was not greater than the steady-state gain variation, and its wavelength dependency was negligible.

• Journal of Internet Computing and Services
• /
• v.10 no.2
• /
• pp.171-177
• /
• 2009

Optical packet switching(OPS) is a strong candidate for the next-generation internet, since it has a fine switching granularity at the packet level for providing flexible bandwidth, and provides seamless integration between WDM layer and IP layer. Optical packet switching have been studied in two categories: OPS in synchronous and OPS in asynchronous networks. In this article we are focused on contention resolution of OPS in asynchronous networks. The hybrid buffer have been addressed, to reduce packet loss further as one of the alternative buffer structures for contention resolution of asynchronous and variable length packets, which consists of the FDL buffer and the electronic buffer. The OPS design issue for the limited number of TWCs and internal wavelengths is important in the aspect of switch cost and resource efficiency. Therefore, an hybrid buffer structured optical packet switch and its scheduling algorithm is presented for considering the limited number of TWCs and internal wavelengths, for contention resolution of asynchronous and variable length packets. The proposed algorithm could lead to the packet loss improvement compared to the legacy LAUC-VF algorithm with only the FDL buffer.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.2
• /
• pp.167-174
• /
• 2012

The circuits including with Optical transceiver and clock data recovery, in this paper, SERDES (SERializer-DESerializer) are implemented to construct a GE-PON burst-mode transceiver supporting IEEE 802.3ah and a jig for measuring the burst-mode characteristics, that is to say, PON upstream optical transmission environment are manufactured to evaluate the performance of transceiver. we verified that the limiting amplifier compensated the gap of max. 26dB optical power by experiments. The startup acquisition lock time is 670ns in case of using VSC7123 and 2300ns in case of S2060 and the data acquisition lock time were measured to be 400ns and 600ns, respectively, in the upstream channel transmission in this work. While on the other, VSC7123 is satisfied with IEEE802.3ah recommendations.