• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.411-413
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• 1999

본 논문에선느 ATM 통신망을 위한 여러 ATM 스위치 모델들 중에서, 내부적으로 블록킹(blocking)이 없고 입출력 단에 각각 버퍼가 할당되어 있는 입출력 버퍼형 교환기에 대하여 연구하였다. 기존에서 스위치 스피드-업(Switch Speed-up) 기법하에서 주로 연구가 이루어졌다. 따라서, 본 논문에서는 유니폼 트래픽하에서 Output-port Expansion 기법을 사용한 귀환.손실 모드 및 하이브리드 모드하에서의 셀 손실률을 비교 분석하였다. Output-port Expansion 기법은, 한 타임 슬롯동안에 입력포트 당 하나의 셀만 교환되며, 만약 하나 이상의 셀들이 같은 출력포트로 향하면, 최대 교환되는 셀 수를 K(Output-port Expansion Ratio)개로 제한하는 방식이다. 유니폼 트래픽(uniform random traffic) 하에서 각 모드에 따른 셀 손실률을 비교 분석한 결과, 로드 0.9를 기점으로, 0.9이하의 로드에서는 하이브리드 모드가, 0.9이상의 로드에서는 손실모드가 가장 낮은 셀 손실률을 보인다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.8A
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• pp.1247-1253
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• 2000

To fully utilize the capabilities of a SONET/ADM network, traffic grooming is needed to multiplex a number of lower-rate traffic streams into a higher-rate stream, and vice versa. Although the capacity of a SONET ring network can be upgraded by operating it over multiple wavelengths, the corresponding network design may be costly if it employs a large number of ADMs. A cost-effective design attempts to minimize the total number of ADMs used in the network while carrying the offered traffic. We introduce and evaluate the performance characteristics of a new traffic-grooming approach for WDM ring networks, called multihop. The multihop implementation places an ADM at each node based on the requested traffic in the traffic-demand matrix then, it tries to groom the wavelengths which can be groomed. We select one of the nodes to be the "hub" node which has an ADM for each wavelength. The hub node, therefore, can "bridge" traffic between all of the wavelengths. The algorithm is specified and illustrated by a simple example. Our results demonstrate that it is beneficial to use a single-hop approach, but for a large grooming ratio and node number, we advocate the use of the multihop approach.e multihop approach.

• The KIPS Transactions:PartC
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• v.9C no.4
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• pp.531-542
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• 2002

An input and output buffering ATM switch conventionally operates in either Queueloss mode or Backpressure mode. Recently, a new mode, which is called Hybrid mode, was proposed to overcome the drawbacks of Queueloss mode and Backpressure mode. In Hybrid mode, when both the destined output buffer and the originfted input buffer are full, a cell is dropped. This thesis analyzes the cell loss rate and the cell delay of Queueloss, Backpressure and Hybrid modes in a switch adopting output-port expansion scheme under uniform traffic. Output-port expansion scheme allows only one cell from an input buffer to be switched during one time slot. If several cells switch to a same destined output port, the number of maximum transfer cells is restricted to K (Output-port expansion ratio). The simulation results show that if an offered load is less than 0.9, Hybrid mode has lower cell loss rate than the other modes; otherwise, Queueloss mode illustrates the lowest cell loss rate, which is a different result from previous researches. However, the difference between Hybrid and Queueloss modes is comparably small. As expected, the average cell delay in Backpressure mode is lower than those of Queueloss mode and Hybrid mode, since the cell delay due to the retransmission of higher number of dropped cells in Backpressure mode is not considered.

• 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.