Inter-Domain Path Computation using Improved Crankback Signaling in Label Switched Networks

The paper deals with the problem of finding suboptimal routing paths in multi-domain Internet environment. The proposed solution can be used in traffic enginering with MPLS

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

A Survey on the Path Computation Element (PCE) Architecture

Quality of Service-enabled applications and services rely on Traffic Engineering-based (TE) Label Switched Paths (LSP) established in core networks and controlled by the GMPLS control plane. Path computation process is crucial to achieve the desired TE objective. Its actual effectiveness depends on a number of factors. Mechanisms utilized to update topology and TE information, as well as the latency between path computation and resource reservation, which is typically distributed, may affect path computation efficiency. Moreover, TE visibility is limited in many network scenarios, such as multi-layer, multi-domain and multi-carrier networks, and it may negatively impact resource utilization. The Internet Engineering Task Force (IETF) has promoted the Path Computation Element (PCE) architecture, proposing a dedicated network entity devoted to path computation process. The PCE represents a flexible instrument to overcome visibility and distributed provisioning inefficiencies. Communications between path computation clients (PCC) and PCEs, realized through the PCE Protocol (PCEP), also enable inter-PCE communications offering an attractive way to perform TE-based path computation among cooperating PCEs in multi-layer/domain scenarios, while preserving scalability and confidentiality. This survey presents the state-of-the-art on the PCE architecture for GMPLS-controlled networks carried out by research and standardization community. In this work, packet (i.e., MPLS-TE and MPLS-TP) and wavelength/spectrum (i.e., WSON and SSON) switching capabilities are the considered technological platforms, in which the PCE is shown to achieve a number of evident benefits

Next generation control of transport networks

It is widely understood by telecom operators and industry analysts that bandwidth demand is increasing dramatically, year on year, with typical growth figures of 50% for Internet-based traffic [5]. This trend means that the consumers will have both a wide variety of devices attaching to their networks and a range of high bandwidth service requirements. The corresponding impact is the effect on the traffic engineered network (often referred to as the “transport network”) to ensure that the current rate of growth of network traffic is supported and meets predicted future demands. As traffic demands increase and newer services continuously arise, novel network elements are needed to provide more flexibility, scalability, resilience, and adaptability to today’s transport network. The transport network provides transparent traffic engineered communication of user, application, and device traffic between attached clients (software and hardware) and establishing and maintaining point-to-point or point-to-multipoint connections. The research documented in this thesis was based on three initial research questions posed while performing research at British Telecom research labs and investigating control of transport networks of future transport networks: 1. How can we meet Internet bandwidth growth yet minimise network costs? 2. Which enabling network technologies might be leveraged to control network layers and functions cooperatively, instead of separated network layer and technology control? 3. Is it possible to utilise both centralised and distributed control mechanisms for automation and traffic optimisation? This thesis aims to provide the classification, motivation, invention, and evolution of a next generation control framework for transport networks, and special consideration of delivering broadcast video traffic to UK subscribers. The document outlines pertinent telecoms technology and current art, how requirements I gathered, and research I conducted, and by which the transport control framework functional components are identified and selected, and by which method the architecture was implemented and applied to key research projects requiring next generation control capabilities, both at British Telecom and the wider research community. Finally, in the closing chapters, the thesis outlines the next steps for ongoing research and development of the transport network framework and key areas for further study