Cloud computing has been the killer technology for offering dynamically scalable infrastructure to modern Internet applications. However, cloud networks can be a burden for latency-sensitive applications such as Tactile Internet, which can't afford the high delay due to communication with remote cloud servers. In this paper, we exploit content distribution networks deployed by Internet service providers, and next-generation passive optical networks to construct agile, programmable and scalable Optical CLoud Distribution Networks (OCLDN). With OCLDN, a software defined networking (SDN)-based mini-cloud data center is installed at the central office, which includes a cloud-based tactile steering server, and supports all types of cloud applications. To meet the stringent quality-of-service (QoS) requirements for new and existing services, we propose a new Dynamic Wavelength and Bandwidth Allocation scheme, which employs the Water-Filling technique and advanced intra-ONU scheduling. Extensive simulations are performed; results highlight the effectiveness of the proposed scheme in supporting the new types of services without impairing the QoS demands for new and legacy data services.

In the LTE EPC, many network entities and interfaces have to be maintained and updated regularly. Moreover, to accommodate more users, new hardware must be integrated, although rarely used. To address these challenges, the EPC can be moved to the cloud using two modern technologies: SDN and NFV. In this paper, we study the impact of integrating these novel technologies on LTE networks. We propose a hybrid approach for selecting whether to apply NFV or SDN on each gateway at a given time while minimizing the network load taking into consideration key network parameters such as the number of active datacenters, the deployment city population, the intensity at a given time, the QoS class identifier (QCI), and the delay budget. We formulate the SDN decomposition/NFV virtualization selection as an optimization problem where the objective is to minimize the network load subject to a set of constraints. Our results show that our proposed solution is more responsive to the dynamic state of the network such that for a given gateway, at a certain time slot, an SDN decomposition might be the optimal choice; while at another time slot with a different network state, the NFV architecture might be more suitable.

Energy efficiency has become a salient element in the design and operation of modern telecommunications networks. To support energy efficiency in passive optical network (PON) systems, the ITU-T has recently standardized a new power management technique, namely the Watchful Sleep mode, which unifies the two previously standardized techniques (i.e., Doze and Cyclic Sleep modes). The new mode can emulate each of the Doze and Cyclic modes, and it outperforms them in terms of energy efficiency and reduced network signaling. In this paper, we present the first analytical model for numerically measure the performance of the Watchful Sleep mode. Specifically, the new model estimates the ONU's energy efficiency under different network scenarios given a set of quality-of-service constraints. To validate our model, we perform comparisons with simulation results. These comparisons demonstrate that the proposed model can accurately capture the energy efficiency of PON systems.

Radio-over-Fiber (RoF) based network architectures would allow centralization of signal processing and signal conditioning functions and simple, cost-effective remote units at the cell site. RoF technology results in remote units with few components, however, certain aspects of the technology may inadvertently lead to high power consuming components. In this paper, we experimentally investigate the effect of electrical-optical-electrical (E/O/E) loss and signal bandwidth on the energy consumption of analog and digitized RoF (ARoF and DRoF) links. We also analyze the energy efficiency of multiple services on a single RoF distribution network. Our results show that E/O/E loss significantly degrades the energy efficiency of the ARoF links. DRoF is robust to the E/O/E loss on the optical link but is affected by the loss due to reconstruction of the radio frequency signal at higher Nyquist zones. We also show that increasing the bandwidth improves the energy efficiency. Finally, we demonstrate that the extra energy savings from having multiple services on a single RoF link depends on the wireless environment.

Next-generation passive optical network (PON) has been considered in the past few years as a cost-effective broadband access technology. With the ever-increasing power saving concern, energy efficiency has been an important issue in its operations. In this paper, we propose a novel sleep-time sizing and scheduling framework for the implementation of green bandwidth allocation (GBA) in TDMA-PONs. The proposed framework leverages the batch-mode transmission feature of GBA to minimize the overhead due to frequent ONU on-off transitions. The optimal sleeping time sequence of each ONU is determined in every cycle without violating the maximum delay requirement. With multiple ONUs possibly accessing the shared media simultaneously, a collision may occur. To address this problem, we propose a new sleep-time sizing mechanism, namely Sort-And-Shift (SAS), in which the ONUs are sorted according to their expected transmission start times, and their sleep times are shifted to resolve any possible collision while ensuring maximum energy saving. Results show the effectiveness of the proposed framework and highlight the merits of our solutions .

Passive optical network (PON) is regarded as a promising solution for the broadband bandwidth bottleneck problem. However, due to its passive nature, legacy PON is limited by the static power distribution, which makes it power inefficient. To address this problem, we propose QPAR [4], a Quasi-Passive and Reconfigurable node, which enables dynamic power and wavelength assignment so as to save optical power budget in PON. In this paper, we study the power gains that can be achieved in PON employing QPAR, as well as different factors that may facilitate or prevent real QPAR deployments. We conduct extensive simulations to demonstrate the merits of QPAR. Results show that QPAR can achieve high optical power saving by intelligently redistributing the unnecessary power assigned to “close” optical network units (ONUs) in the network. The saved power can either be used to connect more ONUs, or extend the network reach without increasing the optical power budget.

UltraFlow - also known as Optical Flow Switching (OFS) has been recently presented as an effective technology for large Internet data transfer. In this paper, we propose a novel scheduling mechanism for the Stanford UltraFlow access network, a novel optical access network architecture that offers dual-mode service to the end-users: legacy IP and OFS. The proposed scheme is a hybrid mechanism that combines the batch scheduling technique with existing methods so as to increase the average Flow throughput, while maintaining relatively low traffic latency. Extensive simulations highlight the advantages of the proposed solution and demonstrate its merits.

The integration of Ethernet Passive Optical Networks (EPONs) and IEEE 802.16 (WiMAX) has been lately presented as a promising fiber-wireless (FiWi) broadband access network. Conversely, lightweight layer-2 virtual private networks (VPNs) over FiWi, which can provide bandwidth guarantee to the respective users, were only recently addressed by Dhaini et. al. In this paper, WiMAX-VPON, the framework proposed by Dhaini et. al to support layer-2 VPNs over EPON-WiMAX, is improved to take into account the polling control overhead when distributing the VPN bandwidth. A new generic analytical model is also presented to evaluate the performance of each registered VPN service. Our proposed model, which can also be used to analyze any polling-based FiWi network, applies for wireless and optical domains and provides performance measurements such as packet queuing delay, end-to-end (from wireless user to optical server) packet delay and average queue size. Numerical results are compared with simulation experiments, and show consistency between both outcomes.

At present there is a strong worldwide push towards bringing fiber closer to individual homes and businesses. Another evolutionary step is the cost-effective all-optical integration of fiber-based access and metro networks. STARGATE [1] is an all- optical access-metro architecture which does not rely on costly active devices and makes use of an overlay island of transparency with optical bypassing capabilities. In this paper we propose ONU architectures, and discuss several technical challenges, which allow STARGATE EPONs (SG-EPONs) to evolve in a pay-as-you grow manner while providing backward compatibility with legacy infrastructure and protecting previous investment. Using a simple bandwidth and wavelength allocation, we study the capacity and delay performance of SG-EPON through simulations.

EPONs are designed to deliver services for multiple applications, such as VoIP, standard and high-definition video, interactive video and best effort traffic. We present the first framework that will enable for per-stream/flow QoS protection in EPON networks using a two stage admission control (AC) system. While the first stage enables the ONU to perform flow admission locally according to the bandwidth availability, the second stage allows for global admission control at the OLT. Appropriate bandwidth allocation algorithms are presented as well. An event driven simulation model is implemented to study the effectiveness of the proposed scheme in providing and protecting QoS.

Ethernet Passive Optical Networks (EPONs) are considered the most promising solutions for upgrading the cur- rent congested access networks to enable the delivery of broad- band integrated services. Although current EPON architectures are economically feasible, they are however bandwidth limited. In this paper, we discuss a simple upgrade architecture from EPON to WDM-PON. We present various Dynamic Wavelength and Bandwidth Allocation algorithms (DWBAs) that exploit both inter-channel and intra-channel statistical multiplexing in order to achieve good performance. We use extensive simulation experiments to validate our reasoning. I. INTRODUCTION

Ethernet passive optical networks (EPONs) are being designed to deliver multiple services and applications, such as voice communications (VoIP), standard and high-definition video (STV and HDTV), video conferencing (interactive video) and data traffic access network. However, most of the current work focuses on inter-ONU dynamic bandwidth allocation (DBA) algorithms. In this paper, we concentrate on the intra-ONU bandwidth allocation for different classes of services. We present a new intra-ONU scheduling scheme based on the Deficient Weighted Round Robin (DWRR) scheduling to achieve adaptive fairness among different classes of services. We validate our reasoning by measuring both the end-to-end delay of different traffic along with the jitter performance of high priority traffic using extensive simulation experiments.

Ethernet Passive Optical Network (EPONs) are currently being designed to deliver multiple services and applications, such as voice communications (VoIP), standard and highdefinition video (STV and HDTV), video conferencing (interactive video) and data traffic access network. The emergence of new bandwidth intensive applications and the continuous demand for more bandwidth in a bandwidth limited EPON require an upgrade from current TDM to WDM-based PON which is currently of huge interest in both the academia and industry. In this paper we propose three new Dynamic Bandwidth Allocation (DBAs) schemes for QoS support in WDM-based PON networks. These schemes can comply with any ONU architecture (tunable lasers or multiple fixed transceivers). However, they vary in their performances (i.e. different jitter, delay, bandwidth utilization etc.). We study the performance of these DBAs using extensive simulation experiments.