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Network architecture of an EPON with one optical line terminal (OLT) and N = 5 optical network units (ONUs), each with a different round-trip time (RTT).
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WDM EPONs not only allow for cautious pay-as-you-grow upgrades of single-channel TDM EPONs but also avoid linearly increasing polling cycle times for an increasing number of ONUS. In this article, we first provide a comprehensive overview of the state of the art of TDM EPONs and recently reported dynamic bandwidth allocation algorithms, including d...
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... for access networks. Among others, the topology may be a tree, tree-and-branch, ring, bus, or a com- bination of those in order to provide redundancy, e.g., double rings. Typically, EPONs have a physical tree topology with the central office located at the root and the subscribers con- nected to the leaf nodes of the tree, as illustrated in Fig. 1. At the root of the tree is an optical line terminal (OLT), which is the service provider equipment residing at the cen- tral office. The EPON connects the OLT to multiple optical network units (ONUs) (the customer premises equipment) through a 1:N optical splitter/combiner. An ONU can serve a single residential or business subscriber, ...
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Citations
... Moreover, the original IPACT algorithm employs a single wavelength channel for scheduling. It has been modified to operate with multiple wavelengths in [11], [12] and [13]. The modified IPACT algorithm was proposed for the SSD and MSD architectures [11]. ...
... It has been modified to operate with multiple wavelengths in [11], [12] and [13]. The modified IPACT algorithm was proposed for the SSD and MSD architectures [11]. Additional algorithms have also been proposed: the Water-Fill (WF) [12] to promote fairness in the wavelength utilization and First-Fit (FF) [13] to provide less delay. ...
Federated Learning (FL) is a distributed machine learning type of processing that preserves the privacy of user data, sharing only the parameters of ML models with a common server. The processing of FL requires specific latency and bandwidth demands that must be fulfilled by the operation of the communication network. This paper introduces two Dynamic Wavelength and Bandwidth Allocation algorithms for TWDM-PONs: one based on bandwidth reservation and the other on statistical multiplexing for the Quality of Service provisioning for FL traffic over 50 Gb/s Ethernet Passive Optical Networks.
... Moreover, the original IPACT algorithm employs a single wavelength channel for scheduling. It has been modified to operate with multiple wavelengths in [10], [11] and [12]. The modified IPACT algorithm was proposed for the SSD and MSD architectures [10]. ...
... It has been modified to operate with multiple wavelengths in [10], [11] and [12]. The modified IPACT algorithm was proposed for the SSD and MSD architectures [10]. Additional algorithms have been proposed: the Water-Fill (WF) [11] to promote fairness in the wavelength utilization and First-Fit (FF) [12] to provide less delay. ...
Federated Learning (FL) is a distributed machine learning (ML) type of processing that preserves the privacy of user data, sharing only the parameters of ML models with a common server. The processing of FL requires specific latency and bandwidth demands that need to be fulfilled by the operation of the communication network. This paper introduces a Dynamic Wavelength and Bandwidth Allocation algorithm for Quality of Service (QoS) provisioning for FL traffic over 50 Gb/s Ethernet Passive Optical Networks. The proposed algorithm prioritizes FL traffic and reduces the delay of FL and delay-critical applications supported on the same infrastructure.
... Depending on value generation, the average improvement is around 10% for various numbers of cycles and ONT terminals. Based on these results, we will therefore prefer the offline wavelength scheduling focusing on wavelength groups [33,34]. ...
... ious numbers of cycles and ONT terminals. Based on these results, we will therefore prefe the offline wavelength scheduling focusing on wavelength groups [33,34]. ...
Recently, metropolitan and access communication networks have markedly developed by utilizing a variety of technologies. Their bearer communication infrastructures will be mostly exploiting the optical transmission medium where wavelength division multiplexing techniques will play an important role. This contribution discusses the symmetric sharing of common optical network resources in wavelength and time domains. Wavelength-Division Multiplexed Passive Optical Networks (WDM-PON) attract considerable attention regarding the next generation of optical metropolitan and access networks. The main purpose of this contribution is presented by the analysis of possible scheduling of wavelengths for our novel hybrid network topologies considered for WDM-PON networks. This contribution briefly deploys adequate Dynamic Wavelength Allocation (DWA) algorithms for selected WDM-PON network designs with the provision of traffic protection when only passive optical components in remote nodes are utilized. The main part of this study is focused on the use of wavelength scheduling methods for selected WDM-PON network designs. For evaluation of offline and online wavelength scheduling for novel hybrid network topologies, a simulation model realized in the Matlab programming environment allows to analyze interactions between various metropolitan and access parts in the Optical Distribution Network (ODN) related to advanced WDM-PON network designs. Finally, wavelength scheduling methods are compared from a viewpoint of utilization in advanced WDM-PON networks designs.
... In this case, we can view the simplest case of the wavelength and bandwidth allocation problem (i.e., only one wavelength channel can be assigned to requests) as classical scheduling theory [22], which has been proved to be NP-hard [23]. Specifically, the ONUs in an NG-EPON can be regarded as jobs, and the granted time periods for these ONUs can be regarded as the processing times of the jobs. ...
Next-generation Ethernet passive optical networks (NG-EPONs) were standardized by the IEEE 802.3 Working Group in 2020 [IEEE 802.3ca-2020–IEEE Standard for Ethernet Amendment 9: physical layer specifications and management parameters for 25 Gb/s and 50 Gb/s passive optical networks, 2020]. Due to the channel bonding technology [“Recent progress on 25G EPON and beyond,” in 42nd European Conference on Optical Communication (ECOC) (2016).] adopted by NG-EPONs, multiple wavelengths can be assigned to an optical network unit (ONU) simultaneously, leading to higher peak transmission rates. As a result, assigning traffic in multiple wavelength channels provides greater scheduling flexibility, a higher peak upstream rate, and better upstream transmission performance (i.e., lower latency); however, it leads to the use of high-cost ONUs with multiple transceivers and further increases the total cost of NG-EPONs. Therefore, selecting a proper wavelength deployment scheme is very important when designing future NG-EPONs. In this paper, we focus on the trade-off between ONU cost and the upstream performance in a static scenario, and we develop an integer linear programming model to formulate the problem. In addition, we propose a heuristic wavelength deployment scheme comparison and selection (WDSCS) algorithm to effectively select appropriate wavelength deployment schemes. According to our simulation results, our proposed WDSCS algorithm can efficiently find a finer number of deployment wavelengths to balance the cost of ONUs and the upstream transmission performance. The wavelength deployment schemes for future NG-EPONs can also be specified based on whether network operators prioritize network performance or cost.
... As an award is customized to the task's time frame, challenging assignments of the wavelength are often a matter of scheduling wavelengths or combined time and wavelengths more effectively in the following portion. There are two main Dynamic Bandwidth Allocation scheduling classes in both Wavelength Division Multiplexing [20][21][22][23] as offline and online scheduling. Under the online plan, for example, [24], the Optical Line Terminal will schedule the arrival of the Optical Network Unit message on its report. ...
... Whereas in offline scheduling, e.g. [20], [25], [24], the Optical Line Terminal allows scheduling after the arrival of all Optical Network Unit reports. [26] describes the comparison between offline and online Dynamic Bandwidth Allocation schedules. ...
... In the downstream, it broadcasts data, and in the upstream, the channel is shared on a time-sharing basis between ONUs [8]. In WDM EPON, each ONU has a dedicated wavelength for its downstream and upstream direction [9]. In hybrid EPON, each ONU does not have a unique/dedicated wavelength; thus, it combines time sharing with a large number of wavelength channels in a single architecture [10]. ...
The next-generation Ethernet passive optical network (NG-EPON) is basically classified into two architectures on the basis of the wavelength sharing by the optical network units (ONUs). The single scheduling domain (SSD) and multi-scheduling domain (MSD) EPON are the two different design architectures for NG-EPON. A vital task in NG-EPON is to design dynamic wavelength bandwidth allocation (DWBA) algorithms that can meet the future demands of the network subscribers. A number of DWBA algorithms have been designed for time and wavelength division multiplex (TWDM) EPON. The existing DWBA algorithms for TWDM-EPON could be used in MSD-EPON by making necessary parametric changes. The design and implementation of new DWBA algorithms for MSD-EPON are still required specifically. In this paper, we have proposed a quality of service (QoS)-based DWBA algorithm for NG-EPON. We have comparatively analyzed our proposed DWBA with the existing algorithms like earlier finished time (EFT), weighted bipartite matching (WBM), and earlier finished time with void filling (EFT-VF). The results show that our proposed DWBA algorithm performs better as compared to EFT, WBM, and EFT-VF on the basis of average packet delay and average completion time for NG-EPON.
... However, in the nextgeneration PON stage 2 (NG-PON2) phase, TWDM PON stacks XG-PONs via multiple pairs of wavelengths and all the optical network units (ONUs) use wavelength-tunable transceivers [3]. It is worth noting that such PON evolution will proceed in a pay-asyou-grow approach [4]. That is, the ONUs with high bandwidth demands will be preferentially upgraded by using wavelengthtunable transceivers while the ONUs with low bandwidth demands remain wavelength-fixed. ...
... To support the differentiated bandwidth allocation among the heterogeneous ONUs, two items of the MPCP with WDM extensions [4] are crucial. Firstly, the extended REGISTER_REQ messages sent by ONUs can inform OLT of each ONU's wavelength tunability and available wavelength(s). ...
... The first available (FA) scheme is widely used in the grant scheduling for multi-wavelength PONs [4,11,13,15]. ...
Adopting the pay-as-you-grow approach to upgrade passive optical network (PON) facilities by WDM technology insures the smoothness of the upgrade, and also results in the coexistence of wavelength-fixed/tunable optical network units (ONUs) in WDM/TDM PONs. Dynamic bandwidth allocation (DBA) is the key to support such coexistence of heterogeneous ONUs. Thus, DBA is also the key to support the smooth evolution of PONs. To more fairly coordinate the bandwidth allocation among the coexisting heterogeneous ONUs, a differentiated grant sizing (DGS) scheme is proposed. In DGS, not only the fairness between the wavelength-fixed/tunable ONUs but also the fairness between the lightly/heavily loaded ONUs is taken into account. To further carry out load balancing among wavelengths, a grant scheduling scheme is also proposed to cooperate with the grant sizing scheme. In the grant scheduling scheme, a measure of the ONUs’ flexibility is given, and then the least flexible job first rule (LFJF) is adopted for joint wavelength and time-slot assignment. Finally, to demonstrate the effectiveness of the proposed algorithm, a series of comparative analyses is conducted based on simulation experiments.
... Each building has hundreds of small cells that are flexibly connected to an Sm-GW, as illustrated in Fig. 1.1. Multiple Sm-GWs are then connected to core networks, i.e., the S-GWs and P-GWs, of multiple cellular operators via physical links (e.g., optical or microwave links) [39][40][41][42][43][44][45][46], as illustrated for a single Sm-GW in Fig. 1.2. An SDN orchestrator owned by the university manages the cellular infrastructure of the entire university. ...
Small wireless cells have the potential to overcome bottlenecks in wireless access through the sharing of spectrum resources. A novel access backhaul network architecture based on a Smart Gateway (Sm-GW) between the small cell base stations, e.g., LTE eNBs, and the conventional backhaul gateways, e.g., LTE Servicing/Packet Gateways (S/P-GWs) has been introduced to address the bottleneck. The Sm-GW flexibly schedules uplink transmissions for the eNBs. Based on software defined networking (SDN) a management mechanism that allows multiple operator to flexibly inter-operate via multiple Sm-GWs with a multitude of small cells has been proposed. This dissertation also comprehensively survey the studies that examine the SDN paradigm in optical networks. Along with the PHY functional split improvements, the performance of Distributed Converged Cable Access Platform (DCCAP) in the cable architectures especially for the Remote-PHY and Remote-MACPHY nodes has been evaluated. In the PHY functional split, in addition to the re-use of infrastructure with a common FFT module for multiple technologies, a novel cross functional split interaction to cache the repetitive QAM symbols across time at the remote node to reduce the transmission rate requirement of the fronthaul link has been proposed.
... The continuous growth in Internet-connected devices results in significant increase in data centres' traffic which in turn necessitates the development of scalable, high bandwidth, low power consumption data centre architectures. Optical data centre architectures, precisely Passive Optical Networks (PONs), with their proven performance in access networks can provide efficient solutions to support connectivity inside modern data centres [1]. In this regard, we proposed different novel PON architectures to manage the inter-rack and intra-rack communication of a data centre as in [2][3][4][5][6]. ...
Passive Optical Networks (PONs) with their proven performance in access networks can provide solutions to the challenges facing modern data centres. In this paper, we study a PON architecture where Arrayed Waveguide Grating Routers (AWGRs) and servers are used to route traffic. We optimize the wavelength routing and assignment in the design and show through a benchmark study that the PON data centre architecture reduces the power consumption by 83% compared to the Fat-Tree architecture and 93% compared to the BCube architecture.
... Numerous WDM-PON architectures have been proposed in the literature to address the aforementioned limitations of traditional WDM-PONs [8,9,[23][24][25][26][27][28][29]. To address the former problem, several WDM-PON architectures and protocols that dynamically manage and allocate bandwidth in both time and wavelength dimensions have been proposed [8,9,[23][24][25][26][27][28][29]. ...
... Numerous WDM-PON architectures have been proposed in the literature to address the aforementioned limitations of traditional WDM-PONs [8,9,[23][24][25][26][27][28][29]. To address the former problem, several WDM-PON architectures and protocols that dynamically manage and allocate bandwidth in both time and wavelength dimensions have been proposed [8,9,[23][24][25][26][27][28][29]. Most of these schemes, however, are costly, require many redundant components, and assume complex OLT and ONUs setups, which require tunable transceivers, or an array of fixed transceivers, or both, WDM filters, and wavelength/waveband-selective receivers at both the OLT and ONUs. ...
The phenomenal growth of mobile backhaul capacity required to support the emerging mobile traffic including cellular Long-Term Evolution (LTE), and LTE-Advanced (LTE-A) requires rapid migration from today’s legacy circuit-switched T1/E1 wireline and microwave backhaul technologies to a new fiber-supported, all-packet-based mobile backhaul infrastructure. Mobile backhaul is utilized to backhaul traffic from individual base stations (BSs) to the radio network controller (RNC), which then connects to the mobile operator’s core network or gateway. Many carriers around the world are considering the potential of utilizing the fiber-based passive optical network (PON) access infrastructure as an all-packet-based converged fixed-mobile optical access networking transport architecture to backhaul both mobile and typical wireline traffic. This chapter details the case for backhauling wireless traffic utilizing an optical access network, the various standards and technology options for passive optical networks (PONs), as well as the design of a novel, fully distributed, ring-based WDM-PON architecture that could be utilized for the support of a converged next-generation mobile infrastructure. Further, as in 4G and 5G the radio access network (RAN) becomes a broad concept that describes network transport systems including mobile backhaul, mobile fronthaul, and wireless connections between radio equipment and user devices, a fiber-wireless integrated system is nowadays not only limited to mobile backhaul, which is mainly composed of fixed wires, but also includes mobile fronthaul. Thus, a discussion is also added at the end of this chapter on mobile fronthaul utilizing PON infrastructures.
