http://hdl.handle.net/2117/3101 2013-05-18T23:07:07Z http://hdl.handle.net/2117/18192 Title: Coordinated Computation of Multi-layer Paths via Inter-layer PCE Communication: Standards, Interoperability and Deployment Authors: Chamania, Mohit; González de Dios, Óscar; López, Víctor; Cuaresma, Marta; Drogon, Marek; Jukan, Admela; Masip Bruin, Xavier; Yannuzzi, Marcelo Abstract: The Path Computation Element (PCE) is positioned nowadays as one of the solutions that almost every carrier will eventually deploy. The PCE architecture as well as a number of components, including the PCE Communication Protocol (PCEP), have been standardized by the IETF. However, a number of challenges remain to be solved on its way from standards to deployment. In particular, the existing proposals for multilayer path computation within the PCE framework need to be further developed and tested, before considering their possible integration into operational networks. This is especially true for the interoperability of the various PCE implementations and the extensions such as the Virtual Network Topology Manager (VNTM) which cannot be taken for granted. This paper presents a functional implementation of coordinated computation of multilayer paths supported through inter-layer PCE communication, where one PCE is developed by industry and the other as an open-source effort. To this end, we consider an IP/MPLS network deployed over a Wavelength Switched Optical Network (WSON), each of which deploying its own PCE, in an attempt to create an inter-operable multilayer solution. We discuss the key challenges that the research community will face in this area, which in turn will drive a considerable part of the upcoming efforts in terms of standardization 2013-03-11T18:55:22Z http://hdl.handle.net/2117/18100 Title: Enabling SCI-FI: service-oriented context-aware and intelligent future Internet Authors: González Cela, Alberto José; Germán Duarte, Martín; Alcober Segura, Jesús Ángel; Martin de Pozuelo, Ramon; Pinyol, Francesc; Ghafoor, Kayhan Zrar Abstract: Internet is becoming a huge heterogeneous and dynamic network that is growing beyond its architectural limits. The scaling up of the number of communicating nodes and services is leading the Internet to an architectural crisis which in turn makes it difficult to provide services efficiently considering the requirements and context conditions of users. The Information-Centric Networking (ICN) approach proposes a network where the main paradigm is not an end-to-end communication between hosts, as in the current Internet. Instead, an increasing demand for efficient distribution of content has motivated the development of architectures that focus on information objects. ICN supports the proliferation of services and contents allowing seamless access to them. This work proposes a context-aware service negotiation protocol which will enable to find and compose services whilst meeting requesters’ requirements and, consequently, maximizing the QoE of users. We also provide the main details of a first implementation of the proposed service-oriented solution (SCI-FI) and discuss the gathered results. 2013-03-06T13:15:09Z http://hdl.handle.net/2117/16103 Title: Simple network management provisioning based on quality of experience feedback Authors: Serral Gracià, René; Marín Tordera, Eva; Yannuzzi, Marcelo; Masip Bruin, Xavier; Sánchez López, Sergio Abstract: This paper presents a promising Autonomic Network Management System (ANMS) that allows Service Providers (SPs) to perform efficient network resource provisioning with their Network Operators (NOs). The novelty of our ANMS is that it offers an starting point to use the end-users perceived quality as a metric to manage the network resources. We show that our system is capable of achieving considerable reductions in the operational costs of SPs, while keeping proper bounds in the end-user satisfaction for the offered multimedia services. 2012-06-20T09:44:06Z http://hdl.handle.net/2117/15936 Title: Effcient network performance assessment using Inter-Packet Arrival Times Authors: Serral Gracià, René; Marín Tordera, Eva; Yannuzzi, Marcelo; Masip Bruin, Xavier; Sánchez López, Sergio Abstract: Network performance measurements have been broadly used in order to debug and to assess the reliability of the network. In general performance measurement is a resource consuming process, which in practice derives in hardly scalable systems. However, in order to control and monitor network resource usage and to assess the quality of multimedia traffic, it is broadly accepted that efficient and scalable network performance evaluation infrastructures must be present in nowadays networks. Nevertheless, most of current research is focused on the assessment of the different performance metrics in order to determine if the quality of the delivered service is correct. Differently, the main contribution presented in this paper, relies on the fact that the accurate estimation of the network metrics is generally not necessary, given that it is much more efficient to directly detect service disruptions. To this end, we propose an algorithm to detect anomalies on the service level delivered to the users. Our solution is based on the distance measurement between acquired reference distributions on the Inter-Packet Arrival Times. This simple to measure time-series permit to detect very efficiently QoS disruptions, making of the solution a very good candidate to be used on Service Level Agreement assessment systems, as we prove in our experimental set up, where we evaluate the performance and accuracy of the proposal in a real scenario. 2012-05-29T11:20:33Z http://hdl.handle.net/2117/15935 Title: Quality of experience aware multimedia provisioning with cross-layer network management Authors: Serral Gracià, René; Marín Tordera, Eva; Yannuzzi, Marcelo; Masip Bruin, Xavier; Sánchez López, Sergio Abstract: This paper presents a Cross-layer Network Management System (NMS) that allows Service Providers (SPs) to perform cost-effective network resource reservations with their Network Operators (NOs). The novelty of our NMS is that it offers a fresh and promising approach to use the endusers satisfaction level as the metric to perform the resource management. We show that our system is capable of achieving considerable reductions in the operational costs of SPs, while keeping proper bounds in the end-user satisfaction for the offered multimedia services. 2012-05-29T10:54:14Z http://hdl.handle.net/2117/15870 Title: Towards an efficient Service Level Agreement assessment Authors: Serral Gracià, René; Labit, Yann; Domingo Pascual, Jordi; Owezarski, Philippe Abstract: On-line end-to-end Service Level Agreement (SLA) monitoring is of key importance nowadays. For this purpose, past recent researches focused on measuring (when possible) or estimating (most of the times) network QoS or performance parameters. Up to now, attempts to provide accurate techniques for estimating such parameters have failed. In addition, live reporting of the estimated network status requires a huge amount of resources, and lead to unscalable systems. The originality of the contribution presented in this paper, relies on the statement that the accurate estimation of network QoS parameters is absolutely not required in most cases: specifically it is sufficient to be aware of service disruptions, i.e. when the QoS provided by the network collapses. For this purpose, we propose an algorithm for disruption detection of network services. The proposed solution is based on the use of the wellknown Kullback-Leibler Divergence algorithm. More specifically, we work on simple to measure time series, i.e. received interpacket arrival times. In addition of efficiently detecting network QoS disruptions, the algorithm, also drastically reduces the required resources, and the overhead produced by the traffic collection for scalable SLA monitoring systems. The validity of the proposal is verified both in terms of accuracy and consumed resources in a real testbed, using different traffic profiles. 2012-05-16T10:51:32Z http://hdl.handle.net/2117/15282 Title: An Approach to a Fault Tolerance LISP Architecture Authors: Martínez Manzanilla, Anny Gabriela; Ramírez, Wilson; Germán Duarte, Martín; Serral Gracià, René; Marín Tordera, Eva; Yannuzzi, Marcelo; Masip Bruin, Xavier Abstract: Next Generation Internet points out the challenge of addressing "things" on both a network with (wired) and without (wireless) infrastructure. In this scenario, new efficient and scalable addressing and routing schemes must be sought, since currently proposed solutions can hardly manage current scalability issues on the current global Internet routing table due to for example multihoming practices. One of the most relevant proposals for an addressing scheme is the Locator Identifier Separation Protocol (LISP) that focuses its key advantage on the fact that it does not follow a disruptive approach. Nevertheless, LISP has some drawbacks especially in terms of reachability in the border routers. In face of this, in this paper we propose a protocol so-called LISP Redundancy Protocol (LRP), which provides an interesting approach for managing the reachability and reliability issues common on a LISP architecture, such as those motivated by an inter-domain link failure. 2012-02-21T12:28:02Z http://hdl.handle.net/2117/15213 Title: Bridging the Interoperability Gap Between the Internet and Optical Network Management Systems Authors: Yannuzzi, Marcelo; Masip Bruin, Xavier; González de Dios, Óscar; García Argos, Carlos; Maciejewski, Maciej; Altmann, Jorn Abstract: Despite the efforts made towards the convergence of packet and circuit switched technologies, the isolation between the Internet and the optical Network Management Systems (NMSs) remains unsolved. Today, carriers have nothing but manual means to coordinate the provisioning between the routers and L1 switches, and much less to communicate and coordinate policy rules, or failures between the IP networks and Ethernet/optical networks. In this paper, we outline the strengths of an easy-to-deploy solution, which can overcome the current separation between the IP and the optical NMSs. The solution consists of an adapter(a middle-box), especially designed to provide a simple, reliable, and automated communication channel between the two management layers. The adapter that we conceive will enable automated interoperability between the IP and the optical NMSs, in support of coordinated actions such as: i) IP service provisioning; ii) IP/MPLS offloading; and iii) coordinated self-healing. We contend that our approach not only eliminates the need for large scale integration into a single multi-layer management system, but also bridges the communication gap between two management ecosystems that are currently isolated. 2012-02-17T13:21:01Z http://hdl.handle.net/2117/12682 Title: Quality of experience based provisioning for service providers Authors: Serral Gracià, René; Marín Tordera, Eva; Yannuzzi, Marcelo; Masip Bruin, Xavier; Sánchez López, Sergio Abstract: Nowadays Network Operators (NOs) are providing service guaranties to customers by largely overprovisioning their networks, but as the Internet keeps growing, this approach is unveiling important issues in terms of cost and management of the network. To optimize the resource usage, and to reduce the existing overprovisioning, in this paper we present a Cross-layer Autonomic Network Management System that permits Service Providers to perform cost-effective network resource reservation with their NOs. In our novel approach, we use the end-user satisfaction level as the metric used to perform the resource provisioning. We show that our system is capable of achieving a high reduction in operational costs for the Service Providers, while keeping proper bounds in the end-user satisfaction for the offered services. 2011-05-31T10:44:20Z http://hdl.handle.net/2117/11457 Title: Modeling physical-layer impairments in multi-domain optical networks Authors: Yannuzzi, Marcelo; Marín Tordera, Eva; Serral Gracià, René; Masip Bruin, Xavier; González de Dios, Óscar; Jimenez Chico, Javier; Verchere, Dominique Abstract: The advantages of optical transparency are still confined to the boundaries of a domain, since the optical signals are subject to O/E/O conversions at the border nodes that separate two optical domains. The extension of transparent connections across domains requires advances both in the modeling of the impairments suffered by the optical signals as well as in devising strategies to exploit such models in practice. In this latter regard, one of the main challenges is to design information exchange models and protocols enabling optical bypass without disclosing detailed physical-layer information among domains. In this paper, we focus on the modeling and the exchange of impairmentrelated information between optical domains. We propose a model that conveniently captures the degradation experienced by an optical signal along a lightpath, and describe it use in the frontier between two neighbor domains. Our approach respects the privacy and administrative limits of carrier networks, while enabling the provision of transparent connections beyond domain boundaries. The model and strategies proposed in this paper generalize the contributions made by some of the most relevant works in the field, providing in this way a first attempt toward a unifying view and theory for quantifying the transmission impairments in DWDM optical networks. 2011-02-21T15:25:24Z http://hdl.handle.net/2117/11198 Title: Cross-talk effects on the Regenerator Allocation optimization Authors: Marín Tordera, Eva; Masip Bruin, Xavier; Yannuzzi, Marcelo; Serral Gracià, René; Sánchez López, Sergio Abstract: This paper studies the impact of considering crosstalk effects in the IA-RWA process and in the regenerator allocation algorithms. First of all, we evaluate if the regenerator allocation optimization is still useful when the crosstalk effects are considered. For this end we improve a simple physical model which computes the quality of the signal factor for each optical connection. Until now this physical model was unaware of the physical layer impairments depending on the interference between different optical connections, such as the crosstalk. Following the same simple methodology we add the switching node crosstalk effect to the computation of the quality of the signal factor. Once the new physical model is enhanced we evaluate the impact of the crosstalk on the performance of IA-RWA algorithms that optimize the use of the regenerators; and also we evaluate the impact of different e wavelength assignation techniques. 2011-01-25T12:44:51Z http://hdl.handle.net/2117/11060 Title: Cross-layer multimedia quality enforcement through user aware information in wireless networks Authors: Serral Gracià, René; Yannuzzi, Marcelo; Marín Tordera, Eva; Masip Bruin, Xavier; Sánchez López, Sergio Abstract: Quality assessment of multimedia traffic is a hot topic. In this paper we present a Multimedia Management System, which can be used on-line to assess and guarantee the quality of multimedia traffic in a wired and wireless network. The proposed platform uses both network and application layer metrics to build up a scalable quality assessment framework. The core of this framework provides means for traffic provisioning capabilities by coordinating the network access and usage both from the wireless node and from the network access point. These two combined features permit our platform to guarantee a satisfactory multimedia user experience. We evaluate our proposal by issuing an experimental deployment in a testbed and performing a series of tests under different network situations to demonstrate the Quality of Experience guaranties of our system. The results show that the quality of video perceived by endusers is considerably improved compared to the typical wireless network. 2011-01-17T11:13:09Z http://hdl.handle.net/2117/10163 Title: An overview of quality of experience measurement challenges for video applications in IP Networks Authors: Serral Gracià, René; Cerqueira, E; Curado, Marilia; Yannuzzi, Marcelo; Monteiro, Edmundo; Masip Bruin, Xavier Abstract: The increase in multimedia content on the Internet has created a renewed interest in quality assessment. There is however a main difference from the traditional quality assessment approaches, as now, the focus relies on the user perceived quality, opposed to the network centered approach classically proposed. In this paper we overview the most relevant challenges to perform Quality of Experience (QoE) assessment in IP networks and highlight the particular considerations necessary when compared to alternative mechanisms, already deployed, such as Quality of Service (QoS). To assist on the handling of such challenges we first discuss the different approaches to Quality of Experience assessment along with the most relevant QoE metrics, and then we discuss how they are used to provide objective results about user satisfaction. 2010-11-08T10:25:32Z http://hdl.handle.net/2117/10162 Title: Quality of experience enforcement in wireless networks Authors: Serral Gracià, René; Yannuzzi, Marcelo; Marín Tordera, Eva; Masip Bruin, Xavier; Sánchez López, Sergio Abstract: In this paper we present a Multimedia Wireless Management System, which can be used on-line to assess and guarantee the quality of multimedia traffic in a wireless network. The proposed platform uses both network and application layer metrics to build up a scalable quality assessment of multimedia traffic. Moreover, the system provides traffic provisioning capabilities by coordinating the network access and usage both from the wireless node and from the network access point. These two combined features permit our platform to guarantee a satisfactory multimedia user experience in wireless environments. We evaluate our proposal by issuing an experimental deployment in a testbed and performing a series of tests under different network situations to demonstrate the Quality of Experience guaranties of our system. The results show that the quality of video perceived by end-users is considerably improved compared to the typical wireless network. 2010-11-08T09:58:30Z http://hdl.handle.net/2117/9565 Title: Improving IA-RWA algorithms in translucent networks by regenerator allocation Authors: Marín Tordera, Eva; Martinez, R; Muñoz, R; Casellas, R; Solé Pareta, Josep Abstract: In this paper we present the impact of considering regenerator allocation when selecting routes and wavelengths in translucent networks. In the regular operation of translucent networks, i.e. with dynamic traffic, we assume that a certain number of 3R regenerators are installed in some nodes of the network. These regenerators break the optical transparency of the lightpaths, but allow establishing the optical connections with the required optical signal quality. We show the performance improvement of the MINCOD-Q IA-RWA algorithm when an efficient regenerator allocation policy is employed (optical regeneration is only performed when the signal quality goes bellow a pre-established threshold). Under this policy, the (extended) MINCOD-Q algorithm performs slightly better in terms of blocking probability, but and most important, this figure is obtained with a significant reduction of the number of 3R regenerators installed in the network. 2010-10-08T09:14:11Z