Experimental Validation of Time-Synchronized Operations for Software-Defined Elastic Optical Networks

Elastic optical networks (EON) have been proposed as a solution to efficiently exploit the spectrum resources in the physical layer of optical networks. Moreover, by centralizing legacy generalized multiprotocol label switching control-plane functionalities and providing a global network view, software-defined networking (SDN) enables advanced network programmability valuable to control and configure the technological breakthroughs of EON. In this paper, we review our recent proposal [Optical Fiber Communication Conf., Los Angeles, California, 2017] of time-synchronized operations (TSO) to minimize disruption time during lightpath reassignment in EON. TSO has been recently standardized in SDN, and here we discuss its implementation using NETCONF and OpenFlow in optical networks. Subsequently, we update our analytical model considering an experimental characterization of the WSS operation time. Then, we extend our previous work with an experimental validation of TSO for lightpath reassignment in a five-node metropolitan optical network test-bed. Results validate the convenience of our TSO-based approach against a traditional asynchronous technique given its reduction of disruption time, while both techniques maintain a similar network performance in terms of optical signal-to-noise ratio and optical power budget

End-to-End Path Computer Schemes for Traffic Engineering in Next Generation Multi-Domain Networks

RÉSUMÉ Avec la venue des réseaux de prochaine génération basés sur le paradigme tout-IP et la demande croissante en qualité de service (QdS) des nouvelles applications temps réel, il existe un besoin imminent pour des mécanismes capables de soutenir le trac de bout-en-bout. Les requis de QdS sont souvent décrits par les paramètres de bande passante, délai, gigue, perte de paquets et disponibilité. Ainsi, les opérateurs de réseaux ont un besoin imminent de techniques qui leur permettraient de satisfaire les exigences de QdS des nouvelles applications IP. Le consensus pour subvenir aux exigences de QdS est la pratique de l'ingénierie de trac. L'ingénierie de trac consiste à acheminer le trac de façon optimale en utilisant les ressources disponibles, tout en satisfaisant les contraintes de QdS et celles du réseau. Cela est souvent réalisé en calculant des chemins optimaux par l'ingénierie de trac, qui constitue l'aspect central de cette thèse. En effet, les paramètres de performances de QdS peuvent être satisfaits en choisissant avec soin un chemin qui a assez de bande passante disponible et qui offre un délai et une gigue acceptable. Si la bande passante est réservée le long de ce chemin, la congestion peut être évitée et la perte de paquets peut ainsi être éliminée. En outre, le calcul minutieux des chemins principaux et de recours permet une meilleure disponibilité en cas de panne de lien ou de noeud. De plus, étant donné que le trac est habituellement transporté à travers différents réseaux administratifs, l'aspect inter-domaine du problème ne peut être négligé. Puis, il y a le fait que les réseaux sont de nature multi-couches. Donc, l'ingénierie de trac de bout-en-bout ne peut être atteint que si les aspects inter-domaine et inter-couche sont pris en compte. À cette fin, cette thèse propose un cadre complet pour l'aspect calcul de chemin bout-en-bout de l'ingénierie de trac, divisé en trois volets. Ces volets suivent tous la technologie G/MPLS pour l'acheminement du trac et la réservation de ressources sur les chemins optimaux calculés.---------ABSTRACT With the advent of all-IP Next Generation Networks and the ever increasing Quality of Service (QoS) demands of new real time IP applications, there is a stringent need for mechanisms that allow the end-to-end sustainment of the trac. QoS requirements are usually a set of network performance indicators that need to be satised in order for the IP applications to function properly. Common QoS parameters are the bandwidth, delay, jitter, packet loss and availability. Thus, network operators urgently need to implement solutions enabling them to satisfy the QoS requirements of real time IP applications. The consensus for QoS provisioning is the application of well dened trac engineering mechanisms, which consists in optimally routing the trac using available resources while satisfying QoS and network constraints. This is often achieved by trac engineered path computation, which is the central focus of this thesis. Indeed, the QoS performance parameters can be met by carefully choosing a path that has the available bandwidth, offers the acceptable delay and jitter. If bandwidth is reserved along this path, congestion is avoided and the packet loss performance parameter can also be met. Moreover, careful calculation of primary and backup paths allows high availability in case of node or link failure. Moreover, there is the fact that trac is usually transported across different administrative networks. Then, there is the detail that networks are multi-layer in nature. Thus, true end-to-end trac engineering can only be achieved if inter-domain and inter-layer aspects are both considered. To this end, this thesis proposes an overall framework for the end-to-end trac engineered path computation problem. As discussed below, the framework is subdivided into three separate aspects, all relying on G/MPLS forwarding technology, which enables a controlled routing and the reservation of resources along trac engineered paths. The proposals for each aspect are the outcome of extensive literature review which identify existing solutions, if any, and the reasons of their shortcomings or non-existence. This review limits the direction to be taken to nd a solution, often by using existing standards and protocols. This is extremely important given the fact that the research topic of this thesis is closely tied to problems of near future generation networks. Thus, it is crucial to reuse existing methods and standards as much as possible in order to get the approval of the research community on the proposed solutions. Moreover, each aspect or sub-problem is carefully studied by dening the actual real world dilemmas surrounding it

Conserve and Protect Resources in Software-Defined Networking via the Traffic Engineering Approach

Software Defined Networking (SDN) is revolutionizing the architecture and operation of computer networks and promises a more agile and cost-efficient network management. SDN centralizes the network control logic and separates the control plane from the data plane, thus enabling flexible management of networks. A network based on SDN consists of a data plane and a control plane. To assist management of devices and data flows, a network also has an independent monitoring plane. These coexisting network planes have various types of resources, such as bandwidth utilized to transmit monitoring data, energy spent to power data forwarding devices and computational resources to control a network. Unwise management, even abusive utilization of these resources lead to the degradation of the network performance and increase the Operating Expenditure (Opex) of the network owner. Conserving and protecting limited network resources is thus among the key requirements for efficient networking. However, the heterogeneity of the network hardware and network traffic workloads expands the configuration space of SDN, making it a challenging task to operate a network efficiently. Furthermore, the existing approaches usually lack the capability to automatically adapt network configurations to handle network dynamics and diverse optimization requirements. Addtionally, a centralized SDN controller has to run in a protected environment against certain attacks. This thesis builds upon the centralized management capability of SDN, and uses cross-layer network optimizations to perform joint traffic engineering, e.g., routing, hardware and software configurations. The overall goal is to overcome the management complexities in conserving and protecting resources in multiple functional planes in SDN when facing network heterogeneities and system dynamics. This thesis presents four contributions: (1) resource-efficient network monitoring, (2) resource-efficient data forwarding, (3) using self-adaptive algorithms to improve network resource efficiency, and (4) mitigating abusive usage of resources for network controlling. The first contribution of this thesis is a resource-efficient network monitoring solution. In this thesis, we consider one specific type of virtual network management function: flow packet inspection. This type of the network monitoring application requires to duplicate packets of target flows and send them to packet monitors for in-depth analysis. To avoid the competition for resources between the original data and duplicated data, the network operators can transmit the data flows through physically (e.g., different communication mediums) or virtually (e.g., distinguished network slices) separated channels having different resource consumption properties. We propose the REMO solution, namely Resource Efficient distributed Monitoring, to reduce the overall network resource consumption incurred by both types of data, via jointly considering the locations of the packet monitors, the selection of devices forking the data packets, and flow path scheduling strategies. In the second contribution of this thesis, we investigate the resource efficiency problem in hybrid, server-centric data center networks equipped with both traditional wired connections (e.g., InfiniBand or Ethernet) and advanced high-data-rate wireless links (e.g., directional 60GHz wireless technology). The configuration space of hybrid SDN equipped with both wired and wireless communication technologies is massively large due to the complexity brought by the device heterogeneity. To tackle this problem, we present the ECAS framework to reduce the power consumption and maintain the network performance. The approaches based on the optimization models and heuristic algorithms are considered as the traditional way to reduce the operation and facility resource consumption in SDN. These approaches are either difficult to directly solve or specific for a particular problem space. As the third contribution of this thesis, we investigates the approach of using Deep Reinforcement Learning (DRL) to improve the adaptivity of the management modules for network resource and data flow scheduling. The goal of the DRL agent in the SDN network is to reduce the power consumption of SDN networks without severely degrading the network performance. The fourth contribution of this thesis is a protection mechanism based upon flow rate limiting to mitigate abusive usage of the SDN control plane resource. Due to the centralized architecture of SDN and its handling mechanism for new data flows, the network controller can be the failure point due to the crafted cyber-attacks, especially the Control-Plane- Saturation (CPS) attack. We proposes an In-Network Flow mAnagement Scheme (INFAS) to effectively reduce the generation of malicious control packets depending on the parameters configured for the proposed mitigation algorithm. In summary, the contributions of this thesis address various unique challenges to construct resource-efficient and secure SDN. This is achieved by designing and implementing novel and intelligent models and algorithms to configure networks and perform network traffic engineering, in the protected centralized network controller