QoS control schemes for two-stage Ethernet passive optical access networks

The most promising technology in optical data transmission at the access network nowadays is the Ethernet passive optical network (EPON). In this paper, we study the delay performance of an intelligent fuzzy logic based dynamic bandwidth allocation (IFLDBA) algorithm for EPON. We evaluate the performance of EPONs from the simulation perspective, where IFLDBA will be compared with some other well known algorithms in terms of the packet delay and bandwidth utilization. This performance evaluation reveals that the IFLDBA shows significant improvement in terms of the packet delay and bandwidth utilization as compared to other hierarchical dynamic bandwidth allocation algorithms.

The implications of the main components of dynamic bandwidth allocation (DBA) algorithms in ethernet passive optical networks, namely grant scheduling framework, grant sizing, and grant scheduling, have to date been examined in isolation. In contrast, we conduct a comprehensive throughput-delay comparison study of the three main DBA components; whereby, for each of the DBA components, we consider a range of common mechanisms. Our comparison study considers a number of novel combinations of mechanisms for the individual DBA algorithms, such as the double-phase polling (DPP) scheduling framework combined with limited with excess distribution grant sizing, and shortest propagation delay (SPD) first scheduling. We find that this (DPP, Limited with excess, SPD) combination in conjunction with a novel excess sharing mechanism outperforms previously studied DBA algorithms.

Ethernet Passive Optical Network (EPON) is one of the most promising technologies for FTTX deployed by service providers at the access network. Dynamic Bandwidth Allocation (DBA) for the upstream traffic can help optimize the network bandwidth utilization. This paper discusses a centralized DBA called as Universal DBA (UDBA) algorithm that supports quality of service (QoS) of the upstream traffic. UDBA algorithm is compared with other DBA algorithm to prove its advantages. It shows that UDBA algorithm improves upon expedited forwarding, assured forwarding and best effort delay on average 62.2%, 36.3%, and 23.1% respectively. The fairness index of UDBA algorithm is improved as high as 5.4%.

The use of passive optical networks (PONs) enables access rates of multi-Gbit/sec bandwidth and provision of quality of service for high definition multimedia services. In this paper, we consider and analyse a generic multi-priority dynamic bandwidth allocation (DBA) algorithm for TDM PONs serving multimedia traffic in an upstream link. PON traffic is served strictly according to its priority. We consider this DBA algorithm using two approaches: (i) the algorithm assigns a fixed service quantum to each priority service and (ii) different service quanta are assigned to different priority services. The mean message delay is evaluated using a multiqueue processor sharing (MPS) model and an MPS with Heterogeneous Traffic (MPS-HT) model for the two approaches respectively. The MPS model is a classical processor sharing model limited by the critical assumption that there is egalitarian service sharing among all users, which is inefficient for multimedia applications in PONs. We extend the MPS model to a general MPS-HT model that enables the analysis of message delay performance in the case where the service quanta may be different for different services.

A survey of dynamic bandwidth allocation algorithms for Ethernet Passive Optical Networks

Passive optical networks (PONs) are thought to be the next step in the development of access networks and providing broadband access in the ¿last mile¿ area. Ethernet PON (EPON) gains the most attention from the researchers as it offers highly flexible and cost effective solution. In this paper we propose two high level scheduler algorithms inside the optical line terminal (OLT) and optical network units (ONU). In the proposed dynamic bandwidth allocation (DBA) algorithm, the OLT allocates the bandwidth to the ONUs in proportion to the weight associated with the excess bandwidth available, while the ONU preferentially allocates its bandwidth to queues with a strict or non strict priority order. The algorithms provide dynamic bandwidth allocation and separate the burden of queue management fairly between the customer and the network. This led to less complicated and more intelligent equipment has been used on the customer's premises. We show the results of simulations to validate the effectiveness of algorithms presented and to provide quality of service (QoS) for triple play real time services in Ethernet passive optical networks (EPONs).

Traffic localization-based dynamic bandwidth allocation algorithm for improvement of QoS in peer-to-peer architecture of passive optical networks

Wavelength division multiplexing/time division multiplexing (WDM/TDM) passive optical networks (PON) is being viewed as a promising solution for delivering multiple services and applications. The hybrid WDM / TDM PON uses the wavelength and bandwidth allocation strategy to control the distribution of the wavelength channels in the uplink direction, so that it can ensure the high bandwidth requirements of multiple Optical Network Units (ONUs) while improving the wavelength resource utilization. Through the investigation of the presented dynamic bandwidth allocation algorithms, these algorithms can't satisfy the requirements of different levels of service very well while adapting to the structural characteristics of mixed WDM / TDM PON system. This paper introduces a novel wavelength and bandwidth allocation algorithm to efficiently utilize the bandwidth and support QoS (Quality of Service) guarantees in WDM/TDM PON. Two priority based polling subcycles are introduced in order to increase system efficiency and improve system performance. The fixed priority polling subcycle and dynamic priority polling subcycle follow different principles to implement wavelength and bandwidth allocation according to the priority of different levels of service. A simulation was conducted to study the performance of the priority based polling in dynamic resource allocation algorithm in WDM/TDM PON. The results show that the performance of delay-sensitive services is greatly improved without degrading QoS guarantees for other services. Compared with the traditional dynamic bandwidth allocation algorithms, this algorithm can meet bandwidth needs of different priority traffic class, achieve low loss rate performance, and ensure real-time of high priority traffic class in terms of overall traffic on the network.

The deployment of new 5G services and future demands for 6G make it necessary to increase the performance of access networks. This challenge has prompted the development of new standardization proposals for Passive Optical access Networks (PONs) that offer greater bandwidth, greater reach and a higher rate of aggregation of users per fiber, being Time- and Wavelength-Division Multiplexing (TWDM) a promising technological solution for increasing the capacity by up to 40 Gbps by using several wavelengths. This solution introduces tunable transceivers into the Optical Network Units (ONUs) for switching from one wavelength to the other, thus addressing the ever-increasing bandwidth demands in residential broadband and mobile fronthaul networks based on Fiber to the Home (FTTH) technology. This adds complexity and sources of inefficiency, such as the laser tuning time (LTT) delay, which is often ignored when evaluating the performance of Dynamic Bandwidth Allocation (DBA) mechanisms. We present a novel DBA algorithm that dynamically handles the allocation of bandwidth and switches the ONUs’ lasers from one wavelength to the other while taking LTT into consideration. To optimize the packet delay, we introduce a scheduling mechanism that follows the Longest Processing Time first (LPT) scheduling discipline, which is implemented over the Interleaved Polling with Adaptive Cycle Time (IPACT) DBA. We also provide quality of service (QoS) differentiation by introducing the Max-Min Weighted Fair Share Queuing principle (WFQ) into the algorithm. The performance of our algorithm is evaluated through simulations against the original IPACT algorithm, which we have extended to support multi-wavelengths. With the introduction of LPT, we obtain an improved performance of up to 73% reduction in queue delay over IPACT while achieving QoS differentiation with WFQ.

Ethernet passive optical network (EPON) is a low-cost and high speed solution to the bottleneck problem. We study previous inter-optical network unit (ONU) scheduling algorithm, interleaved polling with stop (IPS).The IPS algorithm needs an idle time period between two consecutive frame transmission cycles on uplink. In this paper, we propose a two-phase cycle dynamic bandwidth allocation (TCDBA) algorithm to increase the channel utilization on uplink through the elimination of the idle period. And, we also evaluate the performance of the proposed algorithm by simulations and confirm its effectiveness.KeywordsEthernet passive optical network (EPON)multipoint control protocol (MPCP)dynamic bandwidth allocation (DBA)

ABSTRACTIn order to manage Quality of Service (QoS) and energy efficiency in the optical access network, an online Dynamic Bandwidth Allocation (DBA) algorithm with adaptive sleep cycle is presented. This DBA algorithm has the ability to allocate an additional bandwidth to the end user within a single sleep cycle whose duration changes depending on the current buffers occupancy. The purpose of this DBA algorithm is to tune the duration of the sleep cycle depending on the network load in order to provide service to the end user without violating strict QoS requests in all network operating conditions.

Passive optical networks (PONs) require a dynamic bandwidth allocation (DBA) algorithm at the optical line terminal for efficient utilization of upstream bandwidth among the optical network units (ONUs) as per the quality of service requirements for each traffic class defined by PON standardizing bodies. The GigaPON access network (GIANT) was the first International Telecommunication Union compliant DBA algorithm, which is further improved by Immediate Allocation with Colorless Grant (IACG) and Efficient Bandwidth Utilization (EBU) algorithms. However, the polling mechanism of IACG and EBU may not report the true bandwidth demand of ONUs during a service interval. Furthermore, ONU scheduling mechanisms give preference to best effort traffic over the assured traffic during recursive allocation cycles in a service interval, which results in an increase in upstream delays for the assured traffic class. This paper presents an improved bandwidth utilization (IBU) algorithm, which rectifies these deficiencies with a novel polling and scheduling mechanism. Experimental results show that IBU improves the mean of upstream delays of type 2 traffic up to 98%, 93%, and 76% and up to 99%, 92%, and 73% for type 3 traffic compared to the GIANT, IACG, and EBU algorithms, respectively. IBU also shows the least frame loss compared to these state-of-the-art algorithms.

With the advances in optical technology, the span of a broadband access network using passive optical network (PON) technology can be increased from today's standard of 20 km to 100 km or higher, and thereby serve a lot more users. Such an extended-reach PON is known as SuperPON in the literature, and we call it a long-reach PON (LR-PON). A major challenge in LR-PON is that the propagation delay (for data as well as signals) between the telecom central office (CO) and the end user is increased by a very significant amount. Now, traditional PON algorithms for scheduling the upstream transmission, such as dynamic bandwidth allocation (DBA) algorithms, may not be sufficient; actually, they may lead to degraded performance because of the long delay of the CO-to- Users control loop. This challenge motivates us to propose and study a multi-thread polling algorithm to effectively and fairly distribute the upstream bandwidth dynamically. This algorithm exploits the benefits of having multiple polling processes running simultaneously and enabling users to send bandwidth requests before receiving acknowledgement from the CO. We compare the proposed algorithm with traditional DBA, and show its advantage on average packet delay. We then analyze and optimize key parameters of the algorithm, such as initiating and tuning multiple threads, inter-thread scheduling, and fairness among users. Numerical results demonstrate the algorithm's advantage to decrease the average packet delay and improve network throughput under varying offered loads.

An efficient dynamic bandwidth allocation (DBA) algorithm with global priority is proposed for upstream Ethernet passive optical network (EPON) in this paper. The algorithm is hierarchical and it ensures that the excessive bandwidth is allocated fairly according to the priority. The simulation is done using MATLAB by comparing Efficient DBA with global priority to Efficient DBA with local priority. The results show an improvement as high as 11% in terms of the bandwidth utilization and 46% in terms of the delay.

Ethernet passive optical networks (EPONs) have emerged as a promising candidate for next-generation broadband access networks. As this technology evolves, the development of efficient dynamic bandwidth allocation (DBA) algorithms has become a key concern. This paper presents the principle and implementation issues of a new DBA scheme. Through detailed analyses some general investigations on the fairness issue and statistical bandwidth multiplexing (SBM) mechanisms existing in EPON are developed. This proposed scheme consistently maintains a robust fairness mechanism in the DBA operation. With the better maintained fairness mechanism, efficient SBM persists at the global level, whereas multiple network performance matrices are improved. Detailed simulation experiments are presented to study the performance and to validate the effectiveness of the proposed algorithm.