Anny Martínez

A survey and taxonomy of ID/Locator Split Architectures

The IP-based addressing scheme currently supporting the whole routing architecture embeds some well-known limitations that may significantly hinder the deployment of new applications and services on the Internet. Indeed, it is widely accepted that the unstoppable growth of Internet users is producing two well-known problems: (1) depletion of addresses, motivated by a design limitation of the currently deployed addressing scheme, and (2) the semantic overload of addresses. The main negative consequences of these problems may be summarized as: (i) exacerbating the geometrical growth of the routing tables, and (ii) affecting other network features, such as traffic engineering and mobility, in terms of resilience and disruption tolerant communications. The relevant consequences that addressing brings to the overall network operation is pushing the networking community to study and propose new addressing architectures that may limit or even remove the negative effects (affecting network performance) stemmed from the currently deployed addressing architecture. To this end, researchers working on this area must have a perfect understanding of the weaknesses and limitations coming up from the nowadays architecture as well as a comprehensive knowledge of the alternatives proposed so far along with the most appealing research trends. Aligned to this scenario, this paper comes up with the aim of assisting the reader to both: (i) get insights about the most prominent limitations of the currently deployed addressing architecture, and (ii) survey the existing proposals based on ID/Locator Split Architectures (ILSAs) including an analysis of pros and cons, as well as a taxonomy aiming at formulating a design space for evaluating and designing existing and future ILSAs.

Network Management Challenges and Trends in Multi-Layer and Multi-Vendor Settings for Carrier-Grade Networks

The exponential growth of Internet traffic gives no respite to the telecommunications industry and is visibly shortening the life-cycle of the technologies used for core networking. To cope with the traffic demand, the industry has primarily focused on the evolution of the data and control planes, and has rapidly made progress in both subjects. However, the innovations in the market have not reached the management plane at the same speed. This stems from a number of factors, most of which point to the segmentation of competencies in managing multi-layer infrastructures. Current carrier-grade networks are organized as multi-layer infrastructures, typically composed of two layers: IP routers deployed in tandem with optical transport nodes. In turn, each of the two layers is typically composed of devices from different vendors, each of which usually supplies its own (proprietary) network management system (NMS). In practice, the lack of broadly accepted mechanisms for enabling interoperability among the different NMSs has led to the isolation of these proprietary systems. As a result, the operation and maintenance tasks on the network are becoming increasingly complex, which is leading to duplication of functions, higher OPEX, and significant delays in the coordination of multi-layer provisioning processes. In this paper, we examine in detail the interoperability challenges of managing multi-layer and multi-vendor carrier-grade networks, and review the current trends and recent standards in the area, with strong focus on industrial advances. We cover the Multi-Technology Operations System Interface (MTOSI) as well as OpenFlow, and analyze their potential impact and reach. We also discuss some of the reasons why relevant carrier-grade management proposals have not been able to fulfill the requirements of Internet service providers (ISPs), and identify a set of features that might help pave the way to market for new management products.

Network coding-based protection scheme for Elastic Optical Networks

Optical technologies are the foundations supporting the current telecommunication network backbones due to the high speed transmissions achieved in fiber optical networks. Traditional optical networks consist of a fixed 50 GHz grid, resulting in a low optical spectrum (OS) utilization, specifically with transmission rates above 100 Gbps. This issue is magnified when network resilience capabilities are required. For instance, proactive protection solutions such as Dedicated Protection (DP) are widely used because of their low recovery time. However, a significant drawback of DP is its high utilization of optical bandwidth. Recently, optical networks are undergoing significant changes with the purpose of providing a flexible grid that can fully exploit the potential of optical networks. This has led to a new network paradigm termed as Elastic Optical Networks (EON). Moreover, a novel strategy referred to as network coding (NC) has been proposed with the aim of improving network throughput. In this paper, we propose a proactive protection scheme so-called E-DPNC* that combines both the advantages concerning network throughput offered by EON and NC, and the low recovery time of a DP scheme, in order to enable network resilience against optical link failures while also reducing the optical spectrum utilization. Our evaluation results show that our solution reduces the OS utilization by 41% compared with conventional protection schemes deployed on fixed grid scenarios.

Applying Information Extraction for Abstracting and Automating CLI-Based Configuration of Network Devices in Heterogeneous Environments

With the continuous growth of current networks, configuration management has become increasingly relevant to the Information and Communication Technologies (ICT) field. Despite numerous standardization efforts, network administrators continue to rely on Command-Line Interfaces (CLIs) to modify and control the configuration of network devices. Nevertheless, network administrators must deal with the complexities that derive from this practice. On one hand, CLI-based configuration hinders the automation of network configuration tasks which are typically required in autonomic management. The only means for achieving a certain degree of automation is the creation of custom scripts, which is neither scalable nor practical, and is the reason why configuration management tasks are mainly performed through manual intervention. On the other hand, CLIs are generally both device and vendor-specific. In the context of heterogeneous network infrastructures—i.e., networks typically composed of multiple devices from different vendors—the use of several CLIs raises serious Operation, Administration and Management (OAM) issues. Moreover, multi-vendor configurations not only differ syntactically. Overall, the utilization of proprietary mechanisms allows neither reusing the configurations nor sharing knowledge consistently between vendors’ domains. Due to this heterogeneity, CLIs typically provide a help feature which is in turn a useful source of knowledge to enable semantic interpretation of a configuration space. The large amount of information a network administrator must learn and manage makes Information Extraction (IE) and other forms of natural language analysis of the Artificial Intelligence (AI) field key enablers for the network device configuration space. In this chapter we present an Ontology-Based Information Extraction (OBIE) System from the Command-Line Interface (CLI) of network devices. This system exploits natural language resources already available in CLIs in order to extract relevant information and automatically build the semantics of each configuration space. Overall, our solution provides network administrators with a simple tool which entirely automates and abstracts the complexities and heterogeneity of underlying configuration environments in order to reduce time and effort in the configuration of network devices. With such a tool, network administrators will no longer have to read hundreds of manuals, and configuration scripts can be automatically updated for new devices or system upgrades. We developed a prototype implementation to show how we complete the loop from the process of IE, to the configuration of network devices and final testing.

Ontology-based information extraction from the configuration command line of network routers

Knowledge extraction is increasingly attracting the attention of researchers from different disciplines, as a means to automate complex tasks that rely on bulk textual resources. However, the configuration of many devices in the networking field continues to be a labor intensive task, based on the human interpretation and manual entry of commands through a text-based user interface. Typically, these Command-Line Interfaces (CLIs) are both device and vendor-specific, and thus, commands differ syntactically and semantically for each configuration space. Because of this heterogeneity, CLIs always provide a “help” feature—i.e., short command descriptions encoded in natural language—aimed to unveil the semantics of configuration commands for network administrators. In this paper, we exploit this feature with the aim of automating the abstraction of device configurations in heterogeneous settings. In particular, we introduce an Ontology-Based Information Extraction (OBIE) system from the Command-Line Interface of network routers. We also present ORCONF, a domain Ontology for the Router CONFiguration domain, and introduce a semantic relatedness measure that quantifies the degree of interrelation among candidate concepts. The results obtained over the configuration spaces of two widely used network routers demonstrate that this is a promising line of research, with overall percentages of precision and recall of 93%, and 91%, respectively.

A techno-economie study of network coding protection schemes

The recent advances in optical technologies pave the way to the deployment of high-bandwidth services. As reliability becomes a mandatory requirement for some of these services, network providers must endow their networks with resilience capabilities. In recent years, network coding protection (NCP) has emerged as a tentative solution aiming at enabling network resilience in a proactive and efficient way. The goal of this paper is to conduct a techno-economic study to evaluate the protection cost required by NCP schemes deployed either at the IP/MPLS or at the Optical layer of a multi-layer network, as well as its impact on both the capital and operational expenditures (CAPEX, OPEX) of a network provider. Our evaluation results show that a significant reduction in both CAPEX and OPEX is obtained with NCP. Indeed, at least a 49% and 52% of CAPEX and OPEX reduction is achieved respectively in comparison with conventional proactive protection schemes.

TEFIS: A single access point for conducting multifaceted experiments on heterogeneous test facilities

A few years ago, an experimental facility composed of networking gear and simulation tools was sufficient for testing the main features of a prototype before the final product could be launched to the Internet market. This paradigm has certainly changed, but the lack of platforms enabling the realistic assessment of the different facets of a product, including cross-cutting trials across different testbeds, poses strong limitations for researchers and developers. In light of this, we present an open platform that offers a versatile combination of heterogeneous experimental facilities called “TEstbed for Future Internet Services” (TEFIS). TEFIS provides a single access point for conducting cutting-edge experiments on testbeds that supply different capabilities, including testbeds dedicated to network performance, software performance, grid computing, and living labs. We shall show that TEFIS covers the entire life-cycle of a multifaceted experiment, with the advantage that a single testrun can seamlessly execute across different experimental facilities. In order to demonstrate the potential and versatility of the TEFIS platform, we describe the deployment of four distinct experiments and provide a set of results highlighting the benefits of using TEFIS. The experiments described in this article cover: (i) the experimentation with an open API called OPENER (which is an open and programmable environment for managing experimentation with SDN applications); (ii) an application for skiers and tourists at the Megeve ski resort in France; (iii) an application that can dynamically adapt the Quality of Experience (QoE) of multimedia services for mobile users; and (iv) an augmented reality workspace for remote education and learning purposes based on videoconferencing.

An Hybrid Prediction-based Routing approach for reducing routing inaccuracy in optical transport networks

The advent of network technologies such as Automatically Switched Optical Networks (ASON) and Generalized Multiprotocol Label Switching (GMPLS) pave the way to the deployment of flexible optical transport networks (OTNs). The flexibility of OTNs is a feature highly demanded in dynamic scenarios where lightpaths are continuously set up and torn down on a short-term basis. Unfortunately, the availability and accuracy of network state information in dynamic scenarios are both limited, causing a severe impact on both performance and scalability of Routing and Wavelength Assignment (RWA) algorithms. In this paper we devise a promising routing scheme so-called Hybrid Prediction-based Routing (HPBR). HPBR combines prediction strategies with a novel method to select the most suitable routing metric, aiming at reducing both the dissemination of network state information and the blocking probability. Our findings validate that the proposed scheme significantly reduces the blocking probability compared with other routing schemes, while avoiding the need to periodically disseminate network state information.