Network Virtualization Over Elastic Optical Networks: A Survey of Allocation Algorithms

Network virtualization has emerged as a paradigm for cloud computing services by providing key functionalities such as abstraction of network resources kept hidden to the cloud service user, isolation of different cloud computing applications, flexibility in terms of resources granularity, and on‐demand setup/teardown of service. In parallel, flex‐grid (also known as elastic) optical networks have become an alternative to deal with the constant traffic growth. These advances have triggered research on network virtualization over flex‐grid optical networks. Effort has been focused on the design of flexible and virtualized devices, on the definition of network architectures and on virtual network allocation algorithms. In this chapter, a survey on the virtual network allocation algorithms over flexible‐grid networks is presented. Proposals are classified according to a taxonomy made of three main categories: performance metrics, operation conditions and the type of service offered to users. Based on such classification, this work also identifies open research areas as multi‐objective optimization approaches, distributed architectures, meta‐heuristics, reconfiguration and protection mechanisms for virtual networks over elastic optical networks

Availability-Aware Spare Capacity Allocation with Partially Protected Rings

This thesis work focuses on designing a survivable IP-core network with the minimal investment of spare capacity. A span-oriented spare capacity allocation (SCA) scheme is proposed to satisfy customers' availability requirements in the end-to-end (E2E) sense. The novelty of the proposed SCA scheme is that it meets the E2E availability requirements despite the lack of knowledge of E2E bandwidth by employing protection rings covering all links in the network. Different ring selection methods are presented and also compared from the aspect of network redundancy and LP feasibility which provide more flexibility to the design. The proposed SCA algorithm further minimizes total cost of spare capacity by incorporating partial protection within the proposed architecture. The simulation results show that it can significantly reduce the spare capacity consumption depending on the availability. The proposed SCA scheme also performs better in terms of redundancy than that of two other dominant methods available these days

Software Defined Applications in Cellular and Optical Networks

abstract: 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.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201

Optical-WiMAX Hybrid Networks

The emergence of bandwidth-intensive Internet services, such ascircuit-quality voice transfer and interactive video gaming, createa high demand for a very qualified next-generation access network.In addition to high bandwidth, these future access networks shouldalso provide improved network availability, flexibility, mobility,reliability, failure protection, quality of service (QoS) supportand cost-effective access. The integration between optical networksand Worldwide Interoperability for Microwave Access (WiMAX) is apromising solution for future access networks. Accordingly, a fewdifferent architectures and MAC protocol components have recentlybeen proposed for the integration between the Ethernet PassiveOptical Network (EPON) and WiMAX. However, the proposedarchitectures contain several drawbacks. Moreover, the EPON-WiMAXhybrid does not yet contain a comprehensive Medium Access Control(MAC) protocol and a mechanism for Quality of Service (QoS) support.Finally, this work introduces the Resilient Packet Ring (RPR)standard, which aims to build high-performance metro edge and metrocore ring networks that interconnect multiple access networks. Theobjective of this thesis is to examine the integration of opticalstandards, such as RPR and EPON, with the WiMAX standard.Subsequently, this integration will be applied to the areas ofarchitecture and MAC Protocol as a promising solution for not onlyaccess networks but also for metro networks.The first part of the thesis examines the EPON-WiMAX integration asa solution for the access network. Specifically, the proposedsolution includes new EPON-WiMAX hybrid network architectures thatare suitable for both urban and rural environment requirements, andit also introduces a joint MAC protocol for these architectures. Theproposed architectures are reliable and provide extended networkcoverage; in particular, reliability is achieved by applying aprotection scheme to the most critical portion of the EPON part ofthe architecture. Additionally, the network coverage of thearchitecture is extended by inserting an intermediate networkbetween the front end and the backhaul network of the traditionalEPON-WiMAX architecture. Subsequently, we propose a comprehensivejoint MAC protocol for the proposed EPON-WiMAX architecture; thisprotocol provides a per-stream quality-of-service guarantee andimproves the network utilization. Also, the proposed joint MACprotocol includes an admission controller, a scheduler and abandwidth allocator.While the first part of the thesis strives to improve the hybridnetwork reliability through protection in the EPON part and extendthe network coverage through innovative methods, the second partattempts to maintain and enhance these objectives by adding areliable technology to the integrated network. Specifically, thissection examines the way in which the RPR network can be integratedwith the proposed EPON-WiMAX architecture to form an RPR-EPON-WiMAXhybrid network, which can be a solution for both access and metronetworks. The proposed architecture is reliable due to thedependability of the RPR standard and the protection mechanismemployed in the EPON network. Moreover, the architecture contains ahigh fault tolerance against node and connection failure. In thesecond part, the joint MAC protocol for the RPR-EPON-WiMAX hybridnetwork includes a multi-level dynamic bandwidth allocationalgorithm, a distributed admission control, a scheduler, and arouting algorithm. This MAC protocol aims to maximize the advantagesof the proposed architecture by distributing its functionalitiesover the parts of the architecture and jointly executing the partsof the MAC protocol

Network protection with service guarantees

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2013.This electronic version was submitted and approved by the author's academic department as part of an electronic thesis pilot project. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from department-submitted PDF version of thesis.Includes bibliographical references (p. 167-174).With the increasing importance of communication networks comes an increasing need to protect against network failures. Traditional network protection has been an "all-or-nothing" approach: after any failure, all network traffic is restored. Due to the cost of providing this full protection, many network operators opt to not provide protection whatsoever. This is especially true in wireless networks, where reserving scarce resources for protection is often too costly. Furthermore, network protection often does not come with guarantees on recovery time, which becomes increasingly important with the widespread use of real-time applications that cannot tolerate long disruptions. This thesis investigates providing protection for mesh networks under a variety of service guarantees, offering significant resource savings over traditional protection schemes. First, we develop a network protection scheme that guarantees a quantifiable minimum grade of service upon a failure within the network. Our scheme guarantees that a fraction q of each demand remains after any single-link failure, at a fraction of the resources required for full protection. We develop both a linear program and algorithms to find the minimum-cost capacity allocation to meet both demand and protection requirements. Subsequently, we develop a novel network protection scheme that provides guarantees on both the fraction of time a flow has full connectivity, as well as a quantifiable minimum grade of service during downtimes. In particular, a flow can be below the full demand for at most a maximum fraction of time; then, it must still support at least a fraction q of the full demand. This is in contrast to current protection schemes that offer either availability-guarantees with no bandwidth guarantees during the down-time, or full protection schemes that offer 100% availability after a single link failure. We show that the multiple availability guaranteed problem is NP-Hard, and develop solutions using both a mixed integer linear program and heuristic algorithms. Next, we consider the problem of providing resource-efficient network protection that guarantees the maximum amount of time that flow can be interrupted after a failure. This is in contrast to schemes that offer no recovery time guarantees, such as IP rerouting, or the prevalent local recovery scheme of Fast ReRoute, which often over-provisions resources to meet recovery time constraints. To meet these recovery time guarantees, we provide a novel and flexible solution by partitioning the network into failure-independent "recovery domains", where within each domain, the maximum amount of time to recover from a failure is guaranteed. Finally, we study the problem of providing protection against failures in wireless networks subject to interference constraints. Typically, protection in wired networks is provided through the provisioning of backup paths. This approach has not been previously considered in the wireless setting due to the prohibitive cost of backup capacity. However, we show that in the presence of interference, protection can often be provided with no loss in throughput. This is due to the fact that after a failure, links that previously interfered with the failed link can be activated, thus leading to a "recapturing" of some of the lost capacity. We provide both an ILP formulation for the optimal solution, as well as algorithms that perform close to optimal.by Gregory Kuperman.Ph.D

A Review on Provisioning Quality of Service of Wireless Telemedicine for E-Health Services

In general, on-line medical consultation reduces time required for medical consultation induces improvement in the quality and efficiency of healthcare services. All major types of current e-health applications such as ECG, X-ray, video, diagnosis images and other common applications have been included in the scope of the study. In addition, the provision of Quality of Service (QoS) for the application of specific healthcare services in e-health, the scheme of priority for e-health services and the support of QoS in wireless networks and techniques or methods for IEEE 802.11 to guarantee the provision of QoS has also been assessed. In e-health, medical services in remote locations such as rural healthcare centers, ambulances, ships as well as home healthcare services can be supported through the applications of e-health services such as medical databases, electronic health records and the routing of text, audio, video and images. Given this, an adaptive resource allocation for a wireless network with multiple service types and multiple priorities have been proposed. For the provision of an acceptable QoS level to users of e-health services, prioritization is an important criterion in a multi-traffic network. The requirement for QoS provisioning in wireless broadband medical networks have paved the pathway for bandwidth requirements and the real-time or live transmission of medical applications. From the study, good performance of the proposed scheme has been validated by the results obtained. The proposed wireless network is capable of handling medical applications for both normal and life-threatening conditions as characterized by the level of emergencies. In addition, the bandwidth allocation and admission control algorithm for IEEE 802.16- based design specifically for wireless telemedicine/e-health services have also been presented in the study. It has been concluded that under busy traffic conditions, the proposed architecture can used as a feasible and reliable infrastructure network for telemedicine

Towards a Virtualized Next Generation Internet

A promising solution to overcome the Internet ossification is network virtualization in which Internet Service Providers (ISPs) are decoupled into two tiers: service providers (SPs), and infrastructure providers (InPs). The former maintain and customize virtual network(s) to meet the service requirement of end-users, which is mapped to the physical network infrastructure that is managed and deployed by the latter via the Virtual Network Embedding (VNE) process. VNE consists of two major components: node assignment, and link mapping, which can be shown to be NP-Complete. In the first part of the dissertation, we present a path-based ILP model for the VNE problem. Our solution employs a branch-and-bound framework to resolve the integrity constraints, while embedding the column generation process to effectively obtain the lower bound for branch pruning. Different from existing approaches, the proposed solution can either obtain an optimal solution or a near-optimal solution with guarantee on the solution quality. A common strategy in VNE algorithm design is to decompose the problem into two sequential sub-problems: node assignment (NA) and link mapping (LM). With this approach, it is inexorable to sacrifice the solution quality since the NA is not holistic and not-reversible. In the second part, we are motivated to answer the question: Is it possible to maintain the simplicity of the Divide-and-Conquer strategy while still achieving optimality? Our answer is based on a decomposition framework supported by the Primal-Dual analysis of the path-based ILP model. This dissertation also attempts to address issues in two frontiers of network virtualization: survivability, and integration of optical substrate. In the third part, we address the survivable network embedding (SNE) problem from a network flow perspective, considering both splittable and non-splittable flows. In addition, the explosive growth of the Internet traffic calls for the support of a bandwidth abundant optical substrate, despite the extra dimensions of complexity caused by the heterogeneities of optical resources, and the physical feature of optical transmission. In this fourth part, we present a holistic view of motivation, architecture, and challenges on the way towards a virtualized optical substrate that supports network virtualization