QoS Aware Data-Path Routing in DWDM/GMPLS Network

Quality of Service Routing is at present an active and remarkable research area,since most emerging network services require specialized Quality of Service (QoS) functionalities that cannot be provided by the current QoS-unaware routing protocols.w-a-days QoS based data routing is a demanding factor for telecommunication clients.In order to provide better QoS, the service provider network needs to have dynamic light-path provisioning technique. This technique can help to change the quality of the light-path dynamically based on existing traffic load and clients QoS requirements, which can be solved by properly designing Generalized Multi-Protocol Label Switch- ing (GMPLS) capable hybrid network. This network is the combination of physical layer as well as network layer information. In optical networks, physical layer impair- ments (PLIs) incurred by non-ideal optical transmission media, accumulates along the optical path. The overall effect of PLIs determines the feasibility of the light-paths. nce it is impo rtant to understand the process that provide PLI information to the control plane protocols and use this information efficiently to compute feasible routes and wavelengths. Thus, a successful and wide deployment of the most novel network services demands that we thoroughly understand the essence of QoS Routing dynamics, and also that the proposed solutions to this complex problem should be indeed feasible and affordable

Investigation on PCE-based multi-domain optical networks

The last decade has seen many advances in high-speed networking technologies. However, many issues are still open for the development of next generation optical transport networks in order to optimize the resources; this is especially true in the context of multi-domain optical networks. In this context, the IETF entity introduces the Path Computation Elements (PCE) module to improve the network resources occupation. In multi-domain networks, each network domain is usually owned by a different operator/administrator and it entails the reluctant behavior from some operators concerning the dissemination of intra-domain information. The purpose of this work is to present and compare different Traffic Engineering (TE) information dissemination strategies between PCEs in multi-domain optical networks. In such network context, recent studies have found that path computation only with local domain visibility yields poor network performance. Accordingly, certain visibility between domains seems necessary. Aiming to fit the confidentiality requirements of the composing domains and to improve the final network blocking probability, novel link aggregation techniques have been proposed. These techniques summarize the state of network domains resources efficiently. Besides, this aggregated link information is afterwards disseminated to all the remainder domains in the network. In order to fulfill this requirement, we introduce different update triggering policies to make a good trade-off between routing information scalability and inaccuracy. On the other hand, the IETF entity has defined several mechanisms (BRPC and H-PCE) for establishing inter-domain paths to compute routes through cooperation between PCEs. This master thesis proposes a hybrid path computation procedure based on the H-PCE and BRPC. It is important to highlight that the performance of all contributions has been supported by illustrative simulation results

Intelligent Network Infrastructures: New Functional Perspectives on Leveraging Future Internet Services

The Internet experience of the 21st century is by far very different from that of the early '80s. The Internet has adapted itself to become what it really is today, a very successful business platform of global scale. As every highly successful technology, the Internet has suffered from a natural process of ossification. Over the last 30 years, the technical solutions adopted to leverage emerging applications can be divided in two categories. First, the addition of new functionalities either patching existing protocols or adding new upper layers. Second, accommodating traffic grow with higher bandwidth links. Unfortunately, this approach is not suitable to provide the proper ground for a wide gamma of new applications. To be deployed, these future Internet applications require from the network layer advanced capabilities that the TCP/IP stack and its derived protocols can not provide by design in a robust, scalable fashion. NGNs (Next Generation Networks) on top of intelligent telecommunication infrastructures are being envisioned to support future Internet Services. This thesis contributes with three proposals to achieve this ambitious goal. The first proposal presents a preliminary architecture to allow NGNs to seamlessly request advanced services from layer 1 transport networks, such as QoS guaranteed point-to-multipoint circuits. This architecture is based on virtualization techniques applied to layer 1 networks, and hides from NGNs all complexities of interdomain provisioning. Moreover, the economic aspects involved were also considered, making the architecture attractive to carriers. The second contribution regards a framework to develop DiffServ-MPLS capable networks based exclusively on open source software and commodity PCs. The developed DiffServ-MPLS flexible software router was designed to allow NGN prototyping, that make use of pseudo virtual circuits and assured QoS as a starting point of development. The third proposal presents a state of the art routing and wavelength assignment algorithm for photonic networks. This algorithm considers physical layer impairments to 100% guarantee the requested QoS profile, even in case of single network failures. A number of novel techniques were applied to offer lower blocking probability when compared with recent proposed algorithms, without impacting on setup delay time

Mapping time-varying IP traffic to flexible optical paths in flexgrid optical networks

A spectrum slot is the frequency range allocated to a single channel within a flexible grid, and its width needs to be an integer multiple of the so-called slot width granularity. The slot width of the spectrum slots to be used for an optical path in flexgrid optical networks can be adjusted in time to align with time-varying client traffic demand for both bandwidth and energy efficiency purposes. However, frequent adjustment of the slot width of optical paths places substantial signaling load on the control plane. In this paper, an online slot width adjustment mechanism is proposed for flexgrid optical networks under slot width update rate constraints in order to maintain the associated signaling load at acceptable levels. Real traffic traces are used to validate the effectiveness of the proposed mechanism. © 2014, Springer Science+Business Media New York

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