• 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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.367-368
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• 2015

This paper evaluates performance degradation of an NG-EPON (1next-generation Ethernet-passive opticla network) system due to an unused remainder of a grant. Since a packet segmentation is not permitted in NG-EPON, a grant is wasted if the grant size is less than the packet size. Using simulations, we evaluate performance degradation due to the unused remainder.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.11B
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• pp.891-899
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• 2004

Ethernet passive optical network (EPON) has drawn many attention as a promising access network technology because it can provide a high bandwidth with a low cost. Since the uplink in the EPON system is shared by many users, it is necessary for an EPON system to have an efficient bandwidth allocation mechanism. In addition, as the users demand more QoS-oriented applications, it is necessary for an EPON system to have an efficient mechanism supporting QoS. In this paper, we propose a variable window dynamic bandwidth allocation (DBA) algorithm for the EPON system. Unlike the previously proposed DBA algorithms, the variable window algorithm guarantees the QoS for the highest priority class, and at the same time provides more enhanced QoS for the lower priority classes by dynamically allocating bandwidth if necessary. It is verified through the simulations that the variable window algorithm can provide more enhanced QoS performance than other DBA algorithms.

• ETRI Journal
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• v.30 no.2
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• pp.301-307
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• 2008

As broadband access is evolving from digital subscriber lines to optical access networks, Ethernet passive optical networks (EPONs) are considered a promising solution for next generation broadband access. The point-to-multipoint topology of EPONs requires a time-division multiple access MAC protocol for upstream transmission. In this paper, we propose a new enhanced dynamic bandwidth allocation algorithm with fairness called EFDBA for multiple services over EPONs. The proposed algorithm is composed of a fairness counter controller and a fairness system buffer in the optical line terminal. The EFDBA algorithm with fairness can provide increased capability and efficient resource allocation in an EPON system. In the proposed EFDBA algorithm, the optical line termination allocates bandwidth to the optical network units in proportion to the fairness weighting counter number associated with their class and queue length. The proposed algorithm provides efficient resource utilization by reducing the unused remaining bandwidth made by idle state optical network units.

• 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.

• Proceedings of the Optical Society of Korea Conference
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• 2005.02a
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• pp.160-161
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• 2005

A critical issue in implementing efficient Ethernet passive optical network(EPON) System is the bandwidth allocation algorithm. The overall goal of bandwidth allocation is to effectively and fairly perform scheduling of time slots between ONUs in EPON System. We propose a new algorithm of dynamic bandwidth allocation for improved bandwidth efficiency in EPON system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.2
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• pp.130-139
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• 2013

In recent, the communication networks of wind power farm are becoming crucial technologies for monitoring and controlling the large-scale offshore wind power farm. In this paper, EPON based communication network architectures are proposed in order to combat the problems of conventional Ethernet based communication network such as delay, data processing overhead and the fairness of data transmission among turbines in offshore wind power farm. The proposed architecture constructs the point to multi-point network by using OLT and ONUs installed in central control center and wind turbines respectively. The EPON based communication network architecture has low cost, high reliability, and fair transmission capability. To evaluate the performance of proposed architectures, the wind power farm based on IEC 61850 is modelled by using OPNET The simulation results are analyzed and compared with conventional Ethernet based communication network in terms of the overhead, delay and fairness of data transmission.

• 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.

• Journal of the Optical Society of Korea
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• v.13 no.3
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• pp.373-378
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• 2009

An Ethernet passive optical network (EPON) is a low-cost, high-speed solution to the bottleneck problem of a broadband access network. This paper analyzes the delay and the jitter performance of dynamic bandwidth allocation (DBA) schemes for differentiated services in EPONs. Especially, the average packet delay and the delay jitter of the expedited forwarding (EF) traffic class are compared, with consideration as to whether a cyclic or an interleaved polling scheme is superior. This performance evaluation reveals that the cyclic polling based DBA scheme provides constant and predictable average packet delay and improved jitter performance for the EF traffic class without the influence of load variations.