• Journal of Communications and Networks
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• v.7 no.1
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• pp.1-12
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• 2005

Ethernet is being deployed in metropolitan area networks (MANs) as a lower-cost alternative to SONET-based infrastructures. MANs are usually required to support common communication services, such as voice and frame relay, based on legacy synchronous TDM technology in addition to asynchronous packet data transport. This paper addresses the clock synchronization problem that arises when transporting synchronous services over an asynchronous packet infrastructure, such as Ethernet. A novel algorithm for clock synchronization is presented combining time-stamp methods used in the network time protocol (NTP) with signal processing techniques applied to measured packet interarrival times. The algorithm achieves the frequency accuracy, stability, low drift, holdover performance, and rapid convergence required for viable emulation of TDM circuit services over Ethernet.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.10C
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• pp.933-936
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• 2002

One of the problems of a Gigabit-Ethernet system for installation in telecom networks is its relative low reliability compared with SONET, the major telecom network system, which restores from fault within 50 msec. In this study, an optics layer protection for the Gigabit-Ethernet system is proposed. It monitors optical signal quality by comparing the signal level with a calibrated window, and switchs fibers within a time comparable to SONET.

• Journal of Korean Institute of Industrial Engineers
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• v.24 no.4
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• pp.571-578
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• 1998

In this paper, we deal with a node weighted Steiner Ring Problem (SRP) arising from the deployment of Synchronous Optical Networks (SONET), a standard of transmission using optical fiber technology. The problem is to find a minimum weight cycle (ring) covering a subset of nodes in the network considering node and link weights. We have developed two mathematical models, one of which is stronger than the other in terms of LP bounds, whereas the number of constraints of the weaker one is polynomially bounded. In order to solve the problem optimally, we have developed some preprocessing rules and valid inequalities. We have also prescribed an effective heuristic procedure for providing tight upper bounds. Computational results show that the stronger model is better in terms of computation time, and valid inequalities and preprocessing rules are effective for solving the problem optimally.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.3
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• pp.577-585
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• 2004

System Packet Interface Level 4 Phase(SPI-4.2) is an interface for packet and cell transfer between a physical layer(PHY) device and a link layer device, for aggregate bandwidths of OC-192 ATM and Packet Over Sonet/SDH(POS), as well as 10Gbps Ethernet applications. In this paper, we performs the research for SPI-4.2. Also we analyze the performance of SPI-4.2 interface module after modeling using C programming language. This paper shows that SPI-4.2 interface module with 512-word FIFO depth is able to be adapted for the offered loads to 97％ in random uniform traffic and 94％ in bursty traffic with bursty length 32. SPI-4.2 interface module can experience an performance degradation due to heavy overhead when it massively receives small size packets less than 14-byte. SPI-4.2 interface module is suited for line cards in gigabit/terabit routers, and optical cross-connect switches, and SONET/SDH-based transmission systems.

• 정보화사회
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• s.128
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• pp.68-70
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• 1999

두림라인 (주)는 전국적인 링형 망구성의 광통신 기간망 보유, 국내 최초로 공중망에서 B-ISDN (ATM over SONET) 서비스 제공, HFC기반 케이블모뎀을 통한 전국적인 상용화 서비스 1999년내 실현, 한국도로공사의 고속도로 완공과 궤를 같이하여 2005년내 전국 방방곡곡 8개 링형 망구조 확장 등 통신망 부분에 있어서는 21세기 최고의 광통신망 사업자로 발돋음한다는 야심찬 꿈을 키워가고 있다.

• The Magazine of the IEIE
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• v.30 no.2
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• pp.132-142
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• 2003

본 고에서는 광 네트워크 기술과 인터넷 기술 을 결합한 광인터넷에 대하여 지난 제55차 IETF 아틀란타 회의를 포함하여 ITU-T와 OIF (Optical Internet Forum)에서 최근에 활발하게 추진되고 있는 표준화 동향을 살펴본다. 특히, 기존의 MPLS기술을 확장하여 광 네트워크를 경제적으로 제어를 하고 SONET/SDH, TDM, wavelength 및 fiber 등과 같은 모든 광 물리매체를 통합 제어할 수 있는 Generalized MPLS 기술에 대한 표준화 동향을 중점 설명한다.

• The Magazine of the IEIE
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• v.31 no.8
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• pp.73-82
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• 2004

SONET/SDH 전송망에서의 데이터 전송율은 10Gb/s급인 OC-192에서 40Gb/s급인 OC-768 로 발전하였으며, 이더넷 (Ethernet)에서의 데이터 전송율은 1998년 1기가비트 이더넷 기술이 표준화된데 이어 2002년에 10기가비트 이더넷기술의 표준화가 완료되었고 조만간 후속 기술로서 40Gb/s또는 100Gb/s급의 이더넷에 대한 논의가 대두될 것으로 예측된다.(중략)

• TTA Journal
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• s.87
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• pp.149-156
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• 2003

최근 급속하게 증가하는 인터넷 트래픽을 대용량의 광 통신망을 통하여 전달할 수 있는 광 인터넷에 대한 표준화가 활발하게 진행중이다. 본 고에서는 광인터넷에 대하여 현재까지 ITU-T 및 IETF를 중심으로 최근에 추진되고 있는 표준화 동향을 살펴본다. 특히, 광 네트워크의 제어 평면 측면에서 기존의 MPLS 뿐만 아니라 SONET/SDH, wavelength 및 fiber를 통합할 수 있는 GMPLS 기술을 중심으로 표준화 동향을 분석한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.11C
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• pp.1171-1177
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• 2002

In this paper, we proposed a high speed IP(Internet Protocol) packet forwarding engine of ATM(Asynchronous Transfer Mode) based label edge routers for POS(Packet over SONET) interface. The forwarding engine uses TCAM(Ternary Content Addressable Memory) for high performance lookup processing of the packet received from POS interface. We have accomplished high speed IP packet forwarding in hardware by implementing the functions of high speed IP header Processing and lookup control into FPGA(Field Programmable Gate Array). The proposed forwarding engine has the functions of label edge routers as the lookup controller supports MPLS(Multiprotocol Label Switching) packet processing functionality.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.142-145
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• 2001

I did research or design technology of(integration) network of PSTN and PSDN in this paper. Network structure model in association with soft switching and access gateway can create various services based on web and live time and service fee at the rate of bandwidth which can't be provided by existing network based on SONET. Also, interns of capability(function) of each area and construction of local network subscribers, it has great recovery capability by separating each network as local areas. It indicates that it can additionally maximize the application of its own communication network and drastic reduction of communication cost because it is alternated to exclusive usage cost.