• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7B
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• pp.620-627
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• 2003

Ethernet passive optical networks (EPONs) are an emerging access network technology that provide a low-cost method of deploying optical access lines between a carrier's central office and customer sites. Dynamic bandwidth allocation (DBA) provides statistical multiplexing between the optical network units for efficient upstream channel utilization. To support dynamic bandwidth distribution, 1 propose an cyclic polling-based DBA algorithm for differentiated classes of service in EPONs. And, I show that an interleaved polling scheme severely decreases downstream channel capacity for user traffics when the upstream network load is low. To obtain realistic simulation results, I used synthetic traffic that exhibits the properties of self-similarity and long-range dependence I then analyzed the network performance under various loads, specifically focusing on packet delays for different classes of traffic.

• The KIPS Transactions:PartC
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• v.16C no.2
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• pp.217-222
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• 2009

This paper proposes the number of Optical Network Unit (ONU) based priority scheduling mechanism over Ethernet Passive Optical Network (EPON) to support multicast Quality of Service (QoS) for Internet Protocol Television (IPTV) service. Multicast QoS is effected by the receivers' number of a packet because multicast efficiency is determined by how many receivers are received multiple copied packets. Therefore, the proposed mechanism assigns a priority with the number of ONUs to allocate high priority to IPTV services used by many people and firstly transmits a packet with high priority. By doing so, we show that the proposed mechanism support favorite IPTV services with better and stable QoS in spite of congestion.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11b
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• pp.1503-1506
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• 2002

기존 가입자망은 다양한 멀티미디어 서비스 트래픽에 대해 병목으로 작용하였으며 이에 대한 대안으로 광가입자망 기술 대두되었다. 광가입자망은 초기 설치비용이 매우 고가이기 때문에 기술 개발과 설치가 지연되었으나, 비용대비 효율성이 좋은 Passive Optical Network(PON) 기술이 개발됨에 따라 활기를 띠고 있다. 본 고에서는 MPLS/IP 백본으로 연결되는 Ethernet-PON 기반의 광가입자망에서, L2/L3 MPLS 기반의 망사업자가 제공하는 VPN 기술 개발을 위해 Optical Network Unit(ONU) 및 Optical Line Terminal(OLT)에서 지원해야 되는 기능에 대해 연구한다.

• Journal of KIISE:Information Networking
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• v.32 no.2
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• pp.156-166
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• 2005

Ethernet passive optical network is an economical and efficient access network that has received significant research attention in recent years. A MAC(Media Access Control) protocol of PON, the next generation access network, is based on TDMA(Time Division Multiple Access) basically. In this thesis, we addressed the problem of dynamic bandwidth allocation in QoS based Ethernet PONs. We augmented the bandwidth allocation to support QoS in a differentiated services framework. Our differentiated bandwidth guarantee allocation(DBGA) allocates effectively and fairly bandwidths among end users. Moreover, we showed that DBGA that perform weighted bandwidth allocation for high priority packets result in better performance in terms of average and maximum packet delay, as well as network throughput compared with existing dynamic bandwidth allocations. We used simulation experiments to study the performance and validate the effectiveness of the proposed bandwidth allocations.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.23-24
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• 2007

Ethernet passive optical network (EPON) is a technology to solve the access network bottleneck and to realize fiber to the home (FTTH). In EPON, the dynamic bandwidth allocation (DBA) is important because all users share common line in upstream. In this paper, we propose new DBA named as modified EPON dynamic scheduling algorithm (MEDSA) and simulate new DBA using Matlab.

• Journal of Internet Computing and Services
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• v.9 no.4
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• pp.61-68
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• 2008

Ethernet passive optical network (EPON) is the next-generation technology mitigating the bottleneck between high-capacity local area networks (LANs) and a backbone network. The bottleneck is aggrevated depending on burstiness and long range dependence (LRD) of traffic characteristics as well as amount of outgoing traffic from the high-capacity LANs. The proposed scheme decreases average packet delay for data upstreaming by considering such traffic characteristics to dynamically allocate bandwidth to multiple optical network units (ONUs). In addition, it can appropriately support delay-sensitive traffic such as constant bit ratio (CBR) traffic by making maximum cycle time fix regardless of the number of ONUs. The comprehensive simulation results indicate that the proposed scheme acheives up to 77% and 82% lower than previous schemes in terms of average packet delay and average queue size while it limits the maximum cycle time to twice of the basic cycle time.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.608-610
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• 2003

Ethernet PON(Passive Optical Network)에서 핵심 기술 중의 하나인 MAC(Media Access Control) 프로토콜은 ONU(Optical Network틴nit)들이 상향으로 트래픽을 전송할 때 공유되어 있는 링크상의 충돌을 방지하고, 효율적인 대역폭을 할당하기 위한 스케줄링 알고리즘을 포함하고 있다. 본 논문에서는 차세대 가입자 망인 Ethernet PON에서 상향으로의 대역폭 부족을 개선하기 위하여, n개의 파장을 사용한 가변 슬롯 할당 TDMA(Time Division Multiple Access) 방식의 MAC 프로토콜을 제안한다. 이를 검증하기 위하여 OPNET 시뮬레이션 도구를 이용해 Ethernet PON 모델을 설계하고 시뮬레이션 한다.

• Proceedings of the Optical Society of Korea Conference
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• 2005.02a
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• pp.162-163
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• 2005

One of the most important things in EPON(Ethernet Passive Optical Network) is that ONUs(Optical Network Units) have to share a channel in upstream direction. We proposed a new algorithm of Dynamic Bandwidth Allocation using Multiple LLID(Logical Link IDentifier). We show how to allocate bandwidth in Queues for improving performance from Bandwidth using Multiple LLID.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.5B
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• pp.457-465
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• 2003

In this paper, we analyze the performances of variable MAC (Medium Access Control) protocols and present an efficient MAC protocol for Ethernet PON (Passive Optical Network). We consider three MAC protocols: static TDMA, dynamic TDMA, and Interleaved polling. Static TDMA assigns an equal amount of bandwidth to all ONUs regardless of the request information but Dynamic TDMA dynamically allocates the bandwidth to each ONU considering its request. Interleaved Polling operates a cycle with variable time period and a polling method for informing a uplink transmission chance to each ONU. This paper theoretically analyzes the available bandwidth for each of three protocols. We also implement the simulation models for them by using OPNET and evaluates the performances under various bursty traffic environments. The results are compared and analyzed in terms of channel utilization and queueing delay.

• 한국정보통신설비학회:학술대회논문집
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• 2006.08a
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• pp.223-227
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• 2006

HD(High Density) 방송의 시작됨에 따라 광대역 멀티미디어 서비스에 대한 관심이 고조되고 있다. 광대역 멀티미디어 서비스를 하기 위한 전송 매체로 광선로를 이용한 댁내 전송 방식인 FTTH(Fiber To The Home)이 주목받고 있고 특히 AON(Active Optical Network)에 비해 구축, 유지 보수비용에 장점을 가지고 있는 PON을 이용한 방식이 선호되고 있다. PON을 이용한 표준으로 현재 IEEE802.3AH Group에서 표준 완료 된 Gigabit Ethernet PON 있으나 링크 장애에 대한 안정성 고려가 빠져 있다. 이에 본 논문은 멀티미디어 서비스에서 중요시되는 링크 장애에 대한 안정성 확보를 위한 GE-PON Link Protection 방안을 제시하며 OPNET Simulation을 구현하였다.