Fajardo Portillo, Jose Oscar  

ABSTRACT
Taking a look over current mobile implementations, the overhead introduced by the uplink signaling can be prevented reducing the rate of Channel Quality Information reports sent from the mobile users to the channel-aware schedulers located at base stations. In this context, the main goal of the present work is to handle the problem of scheduling traffic flows in modern wireless downlink systems under partially observable channel feedback. With this objective, we focus on the design of an scheduler aimed at minimizing the mean flow delay. In this way, we model the optimization problem as a Partially Observable Markov Decision Process, which depends on the belief state of each users best channel condition. Due to the complexity of the model, we consider the Whittle index-based relaxation, and we derive an index rule which is easily implementable. Whittle indices are obtained offline by means of an algorithm called Adaptive Greedy. The proposed scheduling policy consists in giving priority to the users with the highest Whittle index value. The resulting scheduling solution is then evaluated in both single-class and multi-class scenarios, using real-world channel quality traces in the performed experiments. The obtained results show that the proposed scheduling index rule outperforms the well-known channel-aware disciplines.

ABSTRACT
In the context of cloud-enabled 5G radio access networks with network function virtualization capabilities, we focus on the virtual network function placement problem for a multi-tenant cluster of small cells that provide mobile edge computing services. Under an emerging distributed network architecture and hardware infrastructure, we employ cloud-enabled small cells that integrate micro servers for virtualization execution, equipped with additional hardware appliances. We develop an energy-aware placement solution using a robust optimization approach based on service demand uncertainty in order to minimize the power consumption in the system constrained by network service latency requirements and infrastructure terms. Then, we discuss the results of the proposed placement mechanism in 5G scenarios that combine several service flavours and robust protection values. Once the impact of the service flavour and robust protection on the global power consumption of the system is analyzed, numerical results indicate that our proposal successes to efficiently place the virtual network functions that compose the network services in the available hardware infrastructure while fulfilling service constraints.

ABSTRACT
This paper focuses on multi-tenant 5G networks with virtualization and mobile edge computing capabilities, in the scope of cloud-enabled small cell deployments. In this context, the work here presented deals with the service management and orchestration challenges that arise when handling service mapping on the multi-tenant distributed cloud-enabled radio access network architecture. For that aim, once analysed cloud edge services management and 5G network instantiation in the OpenStack platform, we modify the provided virtual infrastructure manager so as to incorporate virtual network function placement features of the SESAME environment. As main contributions, we adapt the OpenStack application instances to 5G Network Service instantiation, and we include an energy-aware and latency-constrained placement solution.

ABSTRACT
Nowadays, citizens are getting used to new ways of agile communications supporting media-enriched and context-aware information. However, the adoption of these evolved technologies in emergency communications between citizens and public authorities face a series of barrier, including the lack of harmonized and interoperable solutions. Different initiatives worldwide are addressing the need for specifying a stable IP-based next generation emergency communications framework. This paper provides a general overview of the different international approaches with especial focus on the European perspective, where the NG112 architecture has been specified and has now entered the testing and evaluation phase.

ABSTRACT
This paper analyzes current standardization situation of 5G and the role network softwarization plays in order to address the challenges the new generation of mobile networks must face. This paper surveys recent documentation from the main stakeholders to pick out the use cases, scenarios and emerging vertical sectors that will be enabled by 5G technologies, and to identify future high-level service requirements. Driven by those service requirements 5G systems will support diverse radio access technology scenarios, meet end-to-end user experienced requirements and provide capability of flexible network deployment and efficient operations. Then, based on the identified requirements, the paper overviews the main 5G technology trends and design principles to address them. In particular, the paper emphasizes the role played by three main technologies, namely SDN, NFV and MEC, and analyzes the main open issues of these technologies in relation to 5G.

ABSTRACT
5G envisages a hyper-connected society where trillions of diverse entities could communicate with each other anywhere and at any time, some of which will demand extremely challenging performance requirements such as sub-millisecond low latency. Mobile Edge Computing (MEC) concept where application computing resources are deployed at the edge of the mobile network in proximity of an end user is a promising solution to improve quality of online experience. To make MEC more flexible and cost-effective Network Functions Virtualisation (NFV) and Software-Defined Networking (SDN) technologies are widely adopted. It leads to significant CAPEX and OPEX reduction with the help of a joint radio-cloud management and orchestration logic. In this paper we discuss and develop a reference architecture for the orchestration and management of the MEC ecosystem. Along with the lifecycle management flows of MEC services, indicating the interactions among the functional modules inside the orchestrator and with external elements, QoS management with a focus on the channel state information technique is presented.

ABSTRACT
Hurrengo belaunaldiko sareen kudeaketak eskakizun erronkariei aurre egin behar izango die birtualizazio, softwarizazio eta cloud computing bezalako teknologia gaitzaileen aplikazioaren bitartez. Horrelako kudeaketa egoera konplexuan, adimen artifizialaren erabilpena ziklo kognitibo gisa erreminta ezberdintzaile eta ahaltsua bilakatu daiteke sistemaren errendimendu orokorra hobetzeko. Lan honek cloud-ean oinarritutako maila-anitzeko ziklo kognitiboa aurkezten du, aurresandako printzipioak aprobetxatzen dituena, 5G arkitekturaren kontrol eta kudeaketa atazak bermatzeko. Eredu berriztatzaile honek eskema kognitibo zentralizatu eta banatuak konbinatzen ditu modulu erabakitzaileetan sare arkitekturaren maila ezberdinetan, ertza eta cloud ingurunearen arteko elkareragiketa sustatzeko.

ABSTRACT
Adding cognitive capabilities to the wireless networks makes it possible to leverage the control and management information used in the network operation to infer information about the local state and exploit it to improve the overall performance. This paper deals with the combined use of centralized and distributed cognitive cycles integrated at different planes in 5G networks: an integrated data plane, a unified control plane and a cross-layer management plane. This context-aware cognitive schema acts on the decision making modules depending on the monitored environment to prevent failures, balance the virtualized execution and get a global enhancement in the provision of mobile services. The multi-level cognitive cycle supports the interaction between the edge and the cloud blurring the line that separates two paradigms: centralized radio operation and mobile edge services.

ABSTRACT
Current trends in broadband mobile networks are addressed towards the placement of different capabilities at the edge of the mobile network in a centralised way. On one hand, the split of the eNB between baseband processing units and remote radio headers makes it possible to process some of the protocols in centralised premises, likely with virtualised resources. On the other hand, mobile edge computing makes use of processing and storage capabilities close to the air interface in order to deploy optimised services with minimum delay. The confluence of both trends is a hot topic in the definition of future 5G networks. The full centralisation of both technologies in cloud data centres imposes stringent requirements to the fronthaul connections in terms of throughput and latency. Therefore, all those cells with limited network access would not be able to offer these types of services. This paper proposes a solution for these cases, based on the placement of processing and storage capabilities close to the remote units, which is especially well suited for the deployment of clusters of small cells. The proposed cloud-enabled small cells include a highly efficient microserver with a limited set of virtualised resources offered to the cluster of small cells. As a result, a light data centre is created and commonly used for deploying centralised eNB and mobile edge computing functionalities. The paper covers the proposed architecture, with special focus on the integration of both aspects, and possible scenarios of application.

ABSTRACT
Modern broadband mobile networks such as 4G LTE are designed to cope with stringent performance levels, i.e. considerable peak data rates and low latencies. With the wide-spreading of LTE networks all over the world, the access to Internet services through mobile connections is increasing considerably, leading to a plethora of mobile services. However, the inherent characteristics of the radio interface results in variable service performance. First, radio resources are shared among the different mobile users and thus the eNB scheduling functions determine the assigned share of resources for each user in a dynamic way. Moreover, the channel quality of each individual user fluctuates over time due to propagation and fading effects. These aspects introduce new issues in the tasks of performance evaluation and adaptive traffic management at different layers of the protocol stack. Currently, there is a gap between advanced research proposals and the actual network and service performance experienced in commercial mobile networks. Although it is generally assumed that the radio channel may introduce considerable quality fluctuations, there is little evidence of the quality dynamics experienced in live LTE networks at different temporal scales. This PhD work aims at providing some insights of these quality variations by analyzing the Channel State Information generated by UEs. Specifically, the document focuses on the downlink direction and on the effects of using spatial multiplexing techniques. From field testing, the main characteristics of the channel quality are studied at the scale of one second. Besides, LTE emulation tests allow evaluating the characteristics of the reported channel quality at the scale of milliseconds. Therefore, valuable information is captured for different layers of the protocol stack. Finally, the impact of the dynamics of these Channel State Information values into different adaptive traffic management schemes is evaluated. For a comprehensive analysis, different mobile network architectures are considered including classical LTE systems and novel proposals such as centralized radio access networks and mobile edge computing.

ABSTRACT
One of the most challenging problems in mobile broadband networks is how to assign the available radio resources among the different mobile users. Traditionally, research proposals are either specific to some type of traffic or deal with computationally intensive algorithms aimed at optimizing the delivery of general purpose traffic. Consequently, commercial networks do not incorporate these mechanisms due to the limited hardware resources at the mobile edge. Emerging 5G architectures introduce cloud computing principles to add flexible computational resources to Radio Access Networks. This paper makes use of the Mobile Edge Computing concepts to introduce a new element, denoted as Mobile Edge Scheduler, aimed at minimizing the mean delay of general traffic flows in the LTE downlink. This element runs close to the eNodeB element and implements a novel flow-aware and channel-aware scheduling policy in order to accommodate the transmissions to the available channel quality of end users.

ABSTRACT
This paper presents a novel architecture for optimizing the HTTP-based multimedia delivery in multi-user mobile networks. This proposal combines the usual client-driven dynamic adaptation scheme DASH-3GPP with network-assisted adaptation capabilities, in order to maximize the overall Quality of Experience. The foundation of this combined adaptation scheme is based on two state of the art technologies. On one hand, adaptive HTTP streaming with multi-layer encoding allows efficient media delivery and improves the experienced media quality in highly dynamic channels. Additionally, it enables the possibility to implement network-level adaptations for better coping with multi-user scenarios. On the other hand, mobile edge computing facilitates the deployment of mobile services close to the user. This approach brings new possibilities in modern and future mobile networks, such as close to zero delays and awareness of the radio status. The proposal in this paper introduces a novel element, denoted as Mobile Edge-DASH Adaptation Function, which combines all these advantages to support efficient media delivery in mobile multi-user scenarios. Furthermore, we evaluate the performance enhancements of this content- and user context-aware scheme through simulations of a mobile multimedia scenario.

ABSTRACT
This paper deals with the classical problem of radio resource management in LTE MIMO, with special focus to the specific radio channel characteristics in commercial LTE networks. First, we provide some conclusions about the Channel Quality Information traces obtained through field testing. From this analysis, we perform a series of experiments by means of an LTE emulator in order to evaluate the accuracy of different fading models used in the 3GPP. As a first outcome of the paper, we infer several fine-grain channel characteristics useful to feed further research work in the area of LTE MIMO. As a second contribution of the paper, we analyze the performance of classical schedulers (i.e., Round Robin, Best CQI and Proportional Fair) under the obtained LTE MIMO channel conditions. Specifically, we analyze the impact of the channel feedback reporting rate in scenarios with multiple greedy sources.

ABSTRACT
IP Multimedia Subsystem (IMS) is becoming the prevailing candidate for managing future mobile multimedia communications, including critical communications such as public safety, emergency professionals and corporate networks. IMS security and privacy has gained much attention in the few last years. The review of recent IMS security activities stresses the inclusion of intermediate nodes in the media path of secured communications as an open issue. This paper presents an end-to-middle-to-end solution which enables the usage of IMS media plane elements such as recorders, transcoders and novel cross-ciphering functions in a secure way. The proposed solution, which is fully compliant with IMS, includes the network architecture, the signaling plane for session signaling and key management, and the media-plane security characteristics. Experimental results demonstrate that the proposed solution can provide media interoperability (both transcoding and cross-ciphering) with a cost of 17% overhead to a standard IMS call setup in the signaling plane.

ABSTRACT
This paper deals with the analysis of mobile multimedia services, with special focus on current media resolutions for mobile handsets. Since variable network conditions entail variable quality levels, nowadays several applications implement some kind of dynamic service adaptation in order to mitigate these effects. This paper analyzes the service performance from an end-to-end perspective, taking into account the several agents involved in the service provision. From a detailed study, the different possible sources of degradations are identified as well as their impact into the expected quality as perceived by end users. Based on the obtained results, the possible effects of different adaptation capabilities are discussed. The identification of the main source of degradations at the destination endpoint improves the adaptation capabilities and enhances the service performance in terms of perceived quality.

ABSTRACT
Most multimedia applications implement some kind of packet losses analysis mechanism to trigger self–adaptation actions. However, error recovery mechanisms such as ARQ variants avoid packet losses at IP level. Then, there appears an impact into the delay that may indeed result on application–level losses due to samples arriving later than the scheduled playout time. In most cases such degradations are not detected until they are so severe than even losses at IP level appear. We propose a lightweight method that achieves a finer grain estimation. We prove mathematically the capability of modified versions of statistics of delay to predict the error ratio of the wireless link and the load of the wired backhaul. After deducing also simplified heuristics for proposed method, we analyze their estimation capabilities and provide guidance for selecting appropiate parameters.

ABSTRACT
This paper deals with the subjective quality maximization problem when scheduling multimedia traffic flows in a shared channel. In order to quantify such user satisfaction a utility function dependent on flow transfer delay is used. In this context, we formulate the Quality of Experience aware resource allocation optimization problem as a Markov Decision Process. This model is analytically unsolvable in general, and as an approximate solution we develop a simple and tractable index rule based on Gittins approach, originally aimed just at minimizing mean flow delay. As concluded from simulation results, when evaluating subjective quality performance this novel index rule proposal outperforms the most relevant existing scheduling disciplines.

ABSTRACT
Scalable video coding allows an efficient provision of video services at different quality levels with different energy demands. In order to deal with the resulting trade-off we analyze the number of video layers that are worth to be received taking into account the energy constraints. On one hand, a single-objective optimization is proposed based on dynamically selecting the number of layers, which is able to minimize the energy consumption with the constraint of a minimal quality threshold to be reached. However, this approach cannot reflect the fact that the same increment of energy consumption may result on different increments of visual quality. Thus, a multi-objective optimization is proposed and a utility function defined in order to weight the energy consumption and the visual quality criteria. Finally, since the optimization solving mechanism is computationally expensive to be implemented in mobile devices, a heuristic algorithm is proposed. This way mobile operators and end users could significally reduce their energy consumption while keeping reasonable quality levels.

ABSTRACT
This paper deals with the problem of scheduling mobile Internet traffic over a single cell wireless downlink data channel. On the one hand, we compare the performance of different size-based or/and channel-aware scheduling disciplines in mean delay terms, concluding that an approach that combines both size- and channel-awareness is the best alternative, which guarantees acceptable uplink overhead due to channel information reports. On the other hand, we study the impact of different scheduling algorithms on user's satisfaction for web browsing service. As concluded, in order to achieve a trade-off between maximizing overall mean subjective quality and reducing uplink signaling overhead due to channel quality reports, a scheduling policy that benefits from opportunistic gains in combination with a size-aware tie-breaking rule gives the best results.

ABSTRACT
This paper deals with the analysis of user perceived visual quality for mobile multimedia services. H.264/AVC is selected for low resolution video encoding, and a mobile UMTS network is considered for the access to services. First, from subjective tests results, the combined impact of different service- and radio network-level parameters is inferred. As a result, different cross-layer adaptation alternatives are proposed to maximize the perceived quality level under different service conditions. Afterwards, the backhaul segment is considered taking into account possible congestion effects after the aggregation of multi-user media stream. The proposed dynamic adaptation process determines the best combination of media bitrates in order to optimise the overall quality, by making use of information related to network performance both at the radio and backhaul segments.

ABSTRACT
The main scope of the chapter is to present the overall QoE-driven IPTV architecture and the respective perceptual benchmarking of it via a subjective evaluation procedure. The chapter is organized as follows: Section 15.2 presents an overview of all the core components of the adaptive IPTV system (IMS, QoE, Perceptual Cross layer adaptation, network management, etc.). In Section 15.3, the user-centric IPTV architecture is presented, containing NQoS to PQoS mapping operations, the Multimedia Content Management System, the monitoring and adaptation modules presentation, the enhancements of the current IMS functions, and UMTS/ WiMAX technologies QoE/QoS mapping. Section 15.4 analyzes in depth the QoE model used for IPTV cross-layer adaptation. Section 15.5 concludes the benchmarking of the whole architecture, and finally Section 15.6 draws the conclusions.

ABSTRACT
This paper deals with the analysis of user perceived visual quality for mobile multimedia services. H.264/AVC is selected for low resolution video encoding, and 3G UMTS is considered for mobile data services. From subjective tests results, the combined impact of different service– and network–level parameters is inferred. As a result, different cross–layer adaptation alternatives are proposed to maximize the perceived quality level under different service conditions.

ABSTRACT
In this paper, we consider mobile multimedia services delivered over a UMTS network. In this convergent scenario, low level error recovery mechanisms of the access network entail that almost all packet losses are caused by frames arriving at the receiver later than the playout time. Our aim is to find a simplified yet realistic expression for the statistics of the end–to–end delay in order to characterize related application level losses and infer resulting Quality of Experience (QoE). We present a simple and easy to implement model based on empirically obtained parameters that quantitatively reflects the statistical properties of delay. We apply the model to estimate the behavior of application level losses and delay which are the key factors while forecasting QoE in VoIP. Obtained results prove the suitability of the model to be integrated in cross–layer adaptation mechanisms and its utility for dimensioning VoIP playout buffers is also tested.

ABSTRACT
The inclusion of multimedia content in different web-based services has increased significantly. Through an extensive subjective testing campaign, we analyse the quality of experience concerning video transmissions associated to these types of services when accessed from mobile devices and mobile Internet connections. Contrary to traditional normalised quality assessment studies, we point out the service context as a key aspect in quality assessments. Specifically, we analyse the impact of the duration of the test material on quality assessments. We find out that tolerance to visual degradations is higher in the specific context of use compared to when using standardised methodologies for quality assessment, which has a significant impact in terms of commercial service acceptability.

ABSTRACT
This chapter proposes a Content-aware and Network-aware Management System (CNMS) over a converged user-environment of social networking and mobile multimedia. The proposed CNMS will focus on applying dynamic personalized multi-layer adaptation for the optimization of the Quality of Experience (QoE) level in a requested media service according to the users’ preferences, favourites provided in their social network profile, and prior experiences rated by users themselves. By user’s preference extraction, a service/content classification will be performed according to an estimation of the user’s favourites, which will be used to provide optimized media delivery across the delivery chain. Therefore, the end-user will always receive her/his favourite service, like Internet Protocol Television (IPTV), Voice over Internet Protocol (VoIP), interactive application/on-line gaming, web browsing, at requested QoE. The system will ensure optimal allocation of network resources and optimal selection of streaming scheme according to different services/content types and user preferences, and therefore enhance the ratio of price-for-value for the specific subscription and achieve an end-to-end, holistic QoE optimisation. Although QoE is perceived as subjective, it is the only measure that counts for customers of a service. Being able to estimate the user preferences in a controlled manner through the end-user’s social networks profiles, helps operators understand what may be wrong with their services and their respective QoE. The proposed multimodal management system is user-centric and applies advanced machine learning techniques in order to extract user preferences from the social network profile of the user and build up a ranking scale of the services/contents. This ranking scale will be translated to adaptation actions per service type at several instances such as before the provision of the service takes place (i.e. Time Zero), during the delivering of the service (i.e. Time T), across all the network layers and delivery-chain nodes, while ensuring throughout the process that the main focus on the QoS-adaptation of the mobile access network is maintained.

ABSTRACT
Most of the currently available adaptation solutions of VoIP over UMTS are based on the modification of service parameters as the only available reaction against any detected service degradation. On the contrary, in this paper we propose a combined approach where service-level adaptation is considered first and, provided that no suitable parameter combination is capable of providing enough QoE, a change of network state will be suggested. In order to do so we analyze the performance of the end-to-end (e2e) performance metrics in this convergent scenario, the root causes of possible degradations and, finally, the combined effects of the different network segments and their impact on the user perceived QoE. We show the map of best performing VoIP configurations for every state of the network segments. Furthermore, considering each of these configurations, we analyze the acceptability of the service or the convenience of trying to modify the network state. Finally, a lightweight implementation based on simple network state estimation and decision heuristics is proposed and validated in terms of accuracy and responsiveness.

ABSTRACT
The aim of this paper is to present video quality prediction models for objective non-intrusive, prediction of H.264 encoded video for all content types combining parameters both in the physical and application layer over Universal Mobile Telecommunication Systems (UMTS) networks. In order to characterize the Quality of Service (QoS) level, a learning model based on Adaptive Neural Fuzzy Inference System (ANFIS) and a second model based on non-linear regression analysis is proposed to predict the video quality in terms of the Mean Opinion Score (MOS). The objective of the paper is two-fold. First, to find the impact of QoS parameters on end-to-end video quality for H.264 encoded video. Second, to develop learning models based on ANFIS and non-linear regression analysis to predict video quality over UMTS networks by considering the impact of radio link loss models. The loss models considered are 2-state Markov models. Both the models are trained with a combination of physical and application layer parameters and validated with unseen dataset. Preliminary results show that good prediction accuracy was obtained from both the models. The work should help in the development of a reference-free video prediction model and QoS control methods for video over UMTS networks.

ABSTRACT
Future Internet will have to cope with yet unknown terminals and services (even users), in a number and heterogeneity never seen before. So, flexibility or adaptability will be considered as one of the most important design principles. This flexibility will demand different kinds of awareness both in the ends and in every node in the service supplying chain, while targeting users' satisfaction as the final goal of any management process. Although virtualization and “everything is a service” approaches seem to be promising foundations to guarantee this flexibility, Future Internet will be built upon real world mobile wireless network technologies, so that cross-layers issues and quality constraints will persist. Quality of Experience (QoE) could play a significant role there, since it could provide an unified metric, isolating users from low level details or complex NQoS definitions. We will also show an example of how user-aware network tuning mechanisms are able to provide similar users' QoE with lower resources consumption and therefore propose that QoE and *-awareness were considered in the Future Internet design from the very beginning.

ABSTRACT
This paper proposes a service discovery protocol for discovering and advertising services in a proactive ad hoc network. The protocol we have defined is piggybacked into the OLSR protocol. We define a new message type into OLSR called Service Discovery Message (SDM) for both advertisement and discovery of services. The advertisement frequency and advertisement lifetime are user-controlled parameters, so that they can be modified depending on the user requirements. Each node maintains a service cache to store information about its own services, and the services each device discovers in the network. We also present simulation results of our protocol and show that the service discovery protocol defined here achieves much efficiency in discovering services, while it introduces practically no packet overhead compared to the basic OLSR protocol.

ABSTRACT
This paper analyzes different techniques to implement Quality of service (QoS) on multi-tenant 5G networks. Describes the architecture of the next generation mobile network based on cloud-enabled small cell deployments and also proposes an hybrid-cloud solution coexisting with centralized cloud RAN (C-RAN), in order to achieve a gradual implementation of the technology. In this context, the work here presented deals with the challenges of preserving the quality of experience in a multi-tenant cloud enable RAN bearing in mind the Key Performance Indicator (KPI) agreed in the Service Level Agreement (SLA). To achieve this goal, QoS should be managed at different levels of the architecture. Feedback should be given between learning modules in order to analyze the results and infer enhanced decision rules which may conclude in an architecture replacement.

ABSTRACT
This paper focuses on multi-tenant 5G networks with virtualization and mobile edge computing capabilities, in the scope of cloud-enabled small cell deployments. In this context, the work here presented deals with the service management and orchestration challenges that arise when handling service mapping on the multi-tenant distributed cloud-enabled radio access network architecture. For that aim, once analysed cloud edge services management and 5G network instantiation in the OpenStack platform, we modify the provided virtual infrastructure manager so as to incorporate virtual network function placement features of the SESAME environment. As main contributions, we adapt the OpenStack application instances to 5G Network Service instantiation, and we include an energy-aware and latency-constrained placement solution.

ABSTRACT
The SESAME 5G-PPP project targets innovations in three fundamental 5G areas such as the “placement” of network intelligence and applications in the network edge through NFV and cloud computing, the substantial evolution of the Small Cell concept and the consolidation of multitenancy in modern communications infrastructure. A dedicated architecture has been proposed for that purpose. In the present work and taking onto account recent challenges, we discuss latest innovations and/or potential updates of the corresponding architecture, in specific areas covering the SC-Common VNF as fun-in/fun-out module, the progress in SESAME Small Cell functional splits, the placement of “Self-x” features and wireless backhauling. Moreover, we proceed further and analyse the functional description of the related architectural components, in order to promote future improvements.

ABSTRACT
The proper execution of performance tests is of utmost importance for the analysis and evaluation of Internet-related technologies, protocols and deployment strategies. Nowadays, there are plenty of tools available to experimenters ranging from simulation tools, emulation equipment, to small and large scale experimentation testbeds. Each of these performance evaluation frameworks introduces a series of capabilities and drawbacks. Additionally, there is a need for using a common methodology to perform different performance tests and to create comparable outcomes. Seeking for the standardization of reliable and comparable Internet speed measurements and trying to provide end-users with trustworthy measurement tools, different SDOs have standardized both TCP-based and IP-based measurement methodologies. This paper focuses on the applicability of the different measurement frameworks and methodologies in the field of mobile Internet, with special focus on the impact of using TCP over mobile broadband connections. The paper describes a series of experiments over different frameworks and, based on the obtained results, identifies the implications of the different types of performance tests into the evaluation outcomes and states the need for large scale measurements.

ABSTRACT
The Cloud Enabled Small Cell (CESC) concept proposed in EU funded project SESAME has emerged as a promising solution to form a multi-tenant, multi-service architecture at the network edge according to 5G needs. It allows several operators/service providers to engage in a sharing model of both radio access capacity and Mobile Edge Computing (MEC) capabilities. From a business perspective, the shared ecosystem guarantees benefits such as easy system upgrades and CAPEX/OPEX reduction. However, depending on the adapted model which is reflected at Service Level Agreement (SLA) between involved stakeholders, cost and benefit of each party are subject to change. This paper is an effort to identify and analyse different radio and cloud models and pricing schemes for the joint provisioning of radio access capacity and MEC services in a multi-tenant Radio Access Network (RAN).

ABSTRACT
Adding cognitive capabilities to the wireless networks makes it possible to leverage the control and management information used in the network operation to infer information about the local state and exploit it to improve the overall performance. This paper deals with the combined use of centralized and distributed cognitive cycles integrated at different planes in 5G networks: an integrated data plane, a unified control plane and a cross-layer management plane. This context-aware cognitive schema acts on the decision making modules depending on the monitored environment to prevent failures, balance the virtualized execution and get a global enhancement in the provision of mobile services. The multi-level cognitive cycle supports the interaction between the edge and the cloud blurring the line that separates two paradigms: centralized radio operation and mobile edge services.

ABSTRACT
In this manuscript, we will present the main concepts of the 5G-PPP SESAME project dedicated to the implementation of Cloud-Enabled Small Cells (CESCs), able to support edge cloud computing in a multi-tenant, multi-service ecosystem. More particularly, we will present a preview of the SESAME concept at the component/sub-system, system and operation level. At the component/sub-system level, we will detail our plan to deploy multi-operator enabled small cells, enhanced with a virtualised execution platform for 5G. At the system level, we will present the envisaged architecture to manage and control the cloud-enabled small cell infrastructure. Finally, at the operation level, we will explain the potential advantages of adopting the SESAME concept on the 5G access networks.

ABSTRACT
The surge of the Internet traffic with exabytes of data flowing over operators’ mobile networks has created the need to rethink the paradigms behind the design of the mobile network architecture. The inadequacy of the 4G UMTS Long term Evolution (LTE) and even of its advanced version LTE-A is evident, considering that the traffic will be extremely heterogeneous in the near future and ranging from 4K resolution TV to machine-type communications. To keep up with these changes, academia, industries and EU institutions have now engaged in the quest for new 5G technology. In this paper we present the innovative system design, concepts and visions developed by the 5G PPP H2020 project SESAME (Small cEllS coordinAtion for Multi-tenancy and Edge services). The innovation of SESAME is manifold: i) combine the key 5G small cells with cloud technology, ii) promote and develop the concept of Small Cells-as-a-Service (SCaaS), iii) bring computing and storage power at the mobile network edge through the development of non-x86 ARM technology enabled micro-servers, and iv) address a large number of scenarios and use cases applying mobile edge computing.

ABSTRACT
Radio Resource Management (RRM) function is a critical element in multi-user mobile networks. Nowadays, RRM is implemented at the 4G radio edge in order to enhance channelawareness and thus to optimize the efficiency of radio resources, at the cost of high computational requirements at the radio nodes. Current trends towards Network Function Virtualization aim at enabling software-based networking capabilities at different locations of the radio network architecture. This paper analyzes the impact of moving RRM functions to different Radio Access Network locations and with different channel quality feedback periods. Based on simulation results, the paper analyzes the experienced performance of different channel-aware scheduling strategies in the context of multi-user mobile multimedia scenarios with different radio channel conditions.

ABSTRACT
Este artículo trata sobre los esquemas de distribución de contenido multimedia a través de Internet, con especial interés en Internet móvil. Tanto la variabilidad de la calidad de los accesos radio como el incremento del tráfico multimedia plantean nuevos retos en relación a la gestión dinámica de los servicios sobre recursos de red compartidos. En primer lugar, el artículo ofrece una revisión del estado de la tecnología relacionada con el transporte multimedia extremo a extremo. A continuación, el artículo se centra en analizar la evolución de los mecanismos de adaptación dinámica, incluyendo desde esquemas extremo a extremo hasta la gestión dinámica de los recursos de red. Se analizan las posibles ventajas asociadas a nuevas arquitecturas como la computación en la nube móvil y las futuras redes 5G. Finalmente, el artículo identifica una serie de retos y desafíos en la gestión adaptativa de los servicios multimedia en el futuro.

ABSTRACT
One of the most challenging problems in mobile broadband networks is how to assign the available radio resources among the different mobile users. Traditionally, research proposals are either specific to some type of traffic or deal with computationally intensive algorithms aimed at optimizing the delivery of general purpose traffic. Consequently, commercial networks do not incorporate these mechanisms due to the limited hardware resources at the mobile edge. Emerging 5G architectures introduce cloud computing principles to add flexible computational resources to Radio Access Networks. This paper makes use of the Mobile Edge Computing concepts to introduce a new element, denoted as Mobile Edge Scheduler, aimed at minimizing the mean delay of general traffic flows in the LTE downlink. This element runs close to the eNodeB element and implements a novel flow-aware and channel-aware scheduling policy in order to accommodate the transmissions to the available channel quality of end users.

ABSTRACT
This work deals with the problem of scheduling traffic flows in emerging wireless networks. In actual mobile implementations the channel state feedback from the users to the radio schedulers may be deployed based on periodic reports in order to avoid uplink signaling overhead. In this work, we study how to design schedulers under partially observable channels. For that aim, we employ the Whittle index approach using a Partially Observable Markov Decision Process. We further analyze the performance of the derived scheduling solution, both in single-class and multi-class scenarios. Real-world channel quality traces are employed in experiments. Finally, we conclude that the proposed scheduling index rule outperforms well-known channelaware disciplines.

ABSTRACT
This paper deals with the classical problem of radio resource management in LTE MIMO, with special focus to the specific radio channel characteristics in commercial LTE networks. First, we provide some conclusions about the Channel Quality Information traces obtained through field testing. From this analysis, we perform a series of experiments by means of an LTE emulator in order to evaluate the accuracy of different fading models used in the 3GPP. As a first outcome of the paper, we infer several fine-grain channel characteristics useful to feed further research work in the area of LTE MIMO. As a second contribution of the paper, we analyze the performance of classical schedulers (i.e., Round Robin, Best CQI and Proportional Fair) under the obtained LTE MIMO channel conditions. Specifically, we analyze the impact of the channel feedback reporting rate in scenarios with multiple greedy sources.

ABSTRACT
Nowadays there is a growing uncertainty about the near future evolution of classical PMR solutions due to spectrum scarcity, digital dividend issues and economic crisis. This paper aims at facing this situation by seizing the existing window of opportunity due to the convergence of the IMS as a predominant enabler for future multimedia networks and the deployment of commercial LTE networks. The paper details an innovative emergency inter-networking system capable of connecting existing first responder communication systems and enabling the integration of next generation mobile networks by defining technology independent standardized interfaces under the umbrella of IMS. Concerning the experimental outcomes, the paper focuses on the reference implementation to interface with the proposed system.

ABSTRACT
Nowadays, the Critical Communications networks are experiencing the transformation that will lay the foundations for next decades of emergency communications. Although different forums claim for the benefits of different technological solutions, this evolution seems to be driven towards the adoption of commercial radio technologies and mass market devices. Although new standards are being developed by different standardization organizations, the concept of interoperability between Public Safety organizations as a holistic standpoint is still an open issue standards should address in the near future. This paper analyzes the current trends in next generation Critical Communications, and reviews the different efforts carried out by different standardization organizations. It is shown that, although different aspects of interoperability are addressed, an integral interoperability framework is needed. Additionally, the specific area of Operation and Management is discussed as one of the missing pieces. A series of system requirements and design principles are finally provided.

ABSTRACT
This paper analyzes the scenario where multiple users are trying to transmit the same or related content to a common destination through a shared radio access network. A specific aspect of this study is that all users work for a common objective, as it would be the transmission of critical emergency-related media contents to a central operator. We analyze the performance achievable using an LTE cell, with different client-driven autonomous adaptation strategies that take both the network performance and the battery status as input parameters. Remarkable performance results are achieved in terms of number of acceptable uplink video streams in different simulation scenarios. The work would help for designing context- and network-aware adaptation schemes for emergency mobile applications.

ABSTRACT
This paper deals with the performance evaluation of deploying an IMS-based media plane interoperability framework. The 3GPP standards describe two possible operating modes based on either a reactive or a proactive approach. We show that both approaches entail some advantages and drawbacks in terms of signaling overhead and call setup times. In order to use experimental individual delay contributions, a prototype implementation of the required elements was carried out for which transmission and processing times and the average ratio of incompatible calls where evaluated. Additionally, the evaluation focuses on the impact of deploying the interoperability solutions over current UMTS and LTE radio access networks.

ABSTRACT
Currently, the critical communications sector is aware of the need for evolving the portfolio of service capabilities to support advanced multimedia communications in their daily emergency operations. However, there is a discussion about the evolving the private communication networks or adopting commercial network technologies, which have evolved significantly during the last years. This paper presents a process of interaction with critical communication professionals belonging in different professional sectors, different countries and different user profiles. This paper gathers the main findings of this interaction in terms of captured users’ requirements for novel services to be adopted and types of networks which shall support them.

ABSTRACT
Emergency telecommunication systems play an important role in people’s daily life, supporting communication for the public and first responders during emergency related incidents. Nonetheless, the majority of existing emergency communications are limited to traditional voice and text message services due to the data bandwidth constraint of current networks. It is well known that emerging 4G broadband communication technologies have the ability to provide a range of multimedia services (e.g. picture transmission) that could be utilised by the emergency services to save lives. However, a secured emergency conversation cannot be established between incompatible mobile/end devices without the assistance of a security gateway. Therefore, this paper proposes a technology independent security gateway that provides security support for future emergency telecommunication systems. The proposed security gateway works in three modes to cover all the situations in which its assistance is required to establish a secured emergency conversation. In addition, the development process of the security gateway will also be fully discussed in this paper.

ABSTRACT
The great technological evolution achieved in the field of public communication networks in comparison to the slower pace of the critical communications sector has raised discussions regarding the next evolutionary steps of PMR technologies and the integration of mission critical aspects into public wideband networks. This paper analyses a converged scenario of the public and private mobile network technologies which will enable those professionals to make the most of both worlds, while assuring efficient use of critical resources. This paper provides a short overview of the principles that derive from end-user requirements along with a system applicability analysis in a number of complete use cases.

ABSTRACT
This paper presents a novel open-source implementation of a call center, which is compatible with the IP Multimedia Subsystem (IMS) platform, supporting call forwarding and dispatching services, along with video call and chat with file transfer. The proposed solution is called Call Center for IMS (CC4IMS) and following a requirement analysis, the paper discusses the overall architecture and design of the proposed Call Center, focusing on the IMS compatibility and mobility of the implementation. Then, an open-source prototype implementation is presented, which was designed for mobile devices in order to be suitable for distributed and ad-hoc launch at emergency situations by first responder teams near to the location of the emergency incident. Finally, a protocol and message illustration between the CC4IMS and the IMS modules is presented, based on messages that have been actually captured by the CC4IMS prototype and the Open IMS Core, showing that the proposed Call Center confronts with the IMS signaling.

ABSTRACT
This paper deals with the analysis of the impact of different scheduling algorithms on flow level mean delay performance of elastic traffic in a single cell wireless downlink data channel paradigm. An enhanced size-based and channelaware discipline is proposed, which is based on the sized-aware Gittins index approach applied to a time-varying channel context. In order to compare the proposed Opportunistic Gittins rule performance with well-known scheduling algorithms, several simulations have been performed for stochastically arriving flows with Pareto sizes under fading conditions, for different network loads and channel quality indicator reporting rates. As concluded, an approach that combines both flow size-awareness and channel awareness is the best option, which guarantees a trade–off between minimizing uplink overhead due to channel quality reports and improving scheduling performance aimed at reducing overall flow mean delay.

ABSTRACT
The aim of this paper is to assess the impact of devices on Quality of Experience (QoE) of the user. As the types of video content viewed over handheld devices increases e.g. streaming video, it is important to evaluate the impact of the end device on video quality assessment. In this paper subjective tests were conducted with QCIF (176x144) videos over two devices 6 Personal Computer (PC) and mobile handset with 90 test conditions. The dataset was generated with a combination of parameters associated with the access network (block error rates and mean burst lengths), H.264 codec related parameter (sender bitrates) and content types. Subjects favoured PC test over handset test in almost all test scenarios. It was found that as the content activity increases device matters. These studies should help in context-aware services in deciding the encoding parameters based on type of device being used to receive content.

ABSTRACT
This paper deals with the analysis of user perceived visual quality for broadcast mobile TV services, considering energy constraints of mobile devices. A new broadcast multilayering video transmission scheme is proposed to cope with the heterogeneity of mobile devices capabilities, which enables mobile devices to achieve energy savings in accordance to the received visual quality. This new scheme includes audio transmission and still guarantees an acceptable channel switching delay. From subjective tests results, the impact of different service parameters is inferred. As concluded, an approach based on the fine tuning of video layer number and spatial resolution provides the highest achievable QoE level. An advanced decision making process is required to combine both QoE–awareness and energy–awareness.

ABSTRACT
In this paper, we consider mobile multimedia services delivered over a UMTS network. In this convergent scenario, low level error recovery mechanisms of the access network entail that almost all packet losses are caused by frames arriving at the receiver later than the playout time. Our aim is to find a simplified yet realistic expression for the statistics of the end-to-end delay in order to characterize related application level losses and infer resulting Quality of Experience (QoE). We present a simple and easy to implement model based on empirically obtained parameters that quantitatively reflects the statistical properties of delay. We apply the model to estimate the behavior of application level losses and delay which are the key factors while forecasting QoE in VoIP. Obtained results prove the suitability of the model to be integrated in cross-layer adaptation mechanisms and its utility for dimensioning VoIP playout buffers is also tested.

ABSTRACT
This paper deals with the analysis of user perceived visual quality for mobile multimedia services. H.264/AVC is selected for low resolution video encoding, and 3G UMTS is considered for mobile data services. From subjective tests results, the combined impact of different service- and network-level parameters is inferred. As a result, different cross-layer adaptation alternatives are proposed to maximize the perceived quality level under different service conditions.

ABSTRACT
In Universal Mobile Telecommunication System (UMTS) Radio Link Control (RLC) losses severely affect the Quality of Service (QoS) due to high error probability. Therefore, for any video quality prediction model, it is important to model the radio-link loss behaviour. In this paper we evaluate the impact of the radio access network on the end-to-end QoS for H.264 encoded video. In order to characterize the QoS level, a learning model based on Adaptive Neural Fuzzy Inference System (ANFIS) is proposed that takes into account the RLC loss models to predict the video quality in terms of the Mean Opinion Score (MOS). The RLC loss models considered are 2-state Markov models with variable mean burst lengths. The aim of the paper is two-fold. First, to find the impact of QoS parameters in both the physical and application layer on end-to-end video quality. Second, to propose a prediction model based on ANFIS to predict video quality over UMTS networks. ANFIS is well suited for video quality prediction over error prone and bandwidth restricted UMTS as it combines the advantages of neural networks and fuzzy systems. The ANFIS model is trained with a combination of application and physical layer parameters. The performance of the proposed model is validated with unseen dataset. These studies should help in the understanding of the impact of both the application and physical layer parameters on end-to-end video quality and in QoS control methods and adaptation.

ABSTRACT
The Quality of Service (QoS) of Universal Mobile Telecommunication System (UMTS) is severely affected by the losses occurring in Radio Link Control (RLC) due to high error probability. Therefore, for any video quality prediction model, it is important to model the radio-link loss behaviour appropriately. In addition, video content has an impact on video quality under same network conditions. The aim of this paper is to present video quality prediction models for objective, non-intrusive prediction of H.264 encoded video for all content types combining parameters both in the physical and application layer over UMTS networks. In order to characterize the QoS level, a learning model based on Adaptive Neural Fuzzy Inference System (ANFIS) is proposed to predict the video quality in terms of the Mean Opinion Score (MOS). ANFIS is well suited for video quality prediction over error prone and bandwidth restricted UMTS as it combines the advantages of neural networks and fuzzy systems. The loss models considered are 2-state Markov models with variable Mean Burst Lengths (MBLs) depicting the various UMTS scenarios. The proposed model is trained with a combination of physical and application layer parameters and validated with unseen dataset. Preliminary results show that good prediction accuracy was obtained from the model. The work should help in the development of a reference-free video prediction model and Quality of Service (QoS) control methods for video over UMTS networks.

ABSTRACT
Universal Mobile Telecommunication System (UMTS) is a third generation mobile communication systems that supports wireless wideband multimedia applications. The objective of this paper is to present a new model for non-intrusive prediction of H.264 encoded video quality over UMTS networks and to illustrate their application to video quality monitoring and adaptation in mobile wireless streaming services. First, we present an efficient regression model for predicting video quality non-intrusively for all content types. The model is predicted from a combination of a set of objective parameters in the application and physical layer in terms of the Mean opinion Score (MOS). The application layer parameters considered are the content type, sender bitrate and frame rate and the physical layer parameters are the block error rate modeled with 2 state Markov model for a mean burst length of 1.75. The performance of the proposed metric is evaluated with unseen dataset with good prediction accuracy. Second, we illustrate the application of the model in mobile streaming services by presenting a new Sender Bitrate (SBR) adaptation scheme at pre-encoding stage that is Quality of Experience (QoE) driven. The scheme was tested and evaluated in the NS2 based UMTS simulation network. Extensive simulation results demonstrate the effectiveness of the proposed adaptation scheme in terms of the MOS and especially at the UMTS network bottleneck access where perceived video quality is most affected. The proposed scheme was responsive to available network bandwidth and congestion and adapted the SBR accordingly maintaining acceptable quality in terms of the MOS. The proposed scheme has applications in network planning and content provisioning for network/service providers.

ABSTRACT
The provision of video streaming services over mobile data accesses is emerging as a promising service for the current and future Internet. This paper focuses on the study of H.264- based video contents over a typical 3G UMTS connectivity. The performance of the service is finally determined by the combined effects of the encoding features and the radio access characteristics. Therefore, based on the UMTS channel modeling, this paper tries to find out the optimal encoding configuration that provides the best service performance, in terms of Quality of Experience. In addition to other well-known encoding parameters, such as the source target bitrate, frame rate or resolution, this paper studies the impact of the maximum video slice size as a critical parameter for the performance of the considered service.

ABSTRACT
This paper evaluates the performance of VoIP services over mobile accesses, with special focus on currently deployed Best Effort UMTS networks. There are different configuration parameters that have a great impact on end users' perception of quality. This paper tries to help understanding the impact of those parameters, and how they can be tuned for a better VoIP experience.

ABSTRACT
This paper shows the relevance of implementing a dynamic and real-time Voice over IP (VoIP) service adaptation mechanism in order to avoid Perceived Quality of Service (PQoS) degradations. We have studied the most relevant parameters affecting the PQoS experienced by end users in VoIP services over mobile accesses. We will describe the enhancements carried out in the implementation of the simulation model in order to assess VoIP PQoS based on ITU-T E-model and introduce a real-time service adaptation method. This adaptation method involves codec and packetization changes through SIP signalling, jointly to dejittering buffer management, and would be launched upon detection of PQoS degradation, in order to enhance end users' experience.

ABSTRACT
In this paper we present an implementation and validation tests that allow a GNU/Linux node act as a PE router in a BGP/MPLS IP VPN architecture. Precisely, this implementation supports all the mandatory capabilities defined in RFC 4364 with regard to the data forwarding plane, such as VRFs to separate the traffic from different VPNs, MPLS to manage the VPN routes at PE nodes and MPLS tunnels for the communication between PEs. Moreover, this basic implementation is extended to support the operation defined in RFC 4797, which allows other kinds of tunnel technologies to be used between PE nodes. We provide configuration examples for both cases, and finally complete the study with the addition of IPsec options to the PE-PE GRE tunnel communication.

ABSTRACT
This paper presents an implementation of the BGP/MPLS IP VPN functionalities for GNU/Linux. First, we briefly review the operation mode described in the IETF RFC 4364 and show the characteristics that are supported by this implementation. Afterwards, we provide some implementation details of the forwarding plane for the kernel 2.6.18.1. This implementation includes the integration of the MPLS- and VRF-for-Linux projects. Finally, we present some example scenarios to validate our implementation in different cases, and show the corresponding commands for the ingress and egress PE routers. This work establishes a first approach for testing BGP/MPLS IP VPN technology in GNU/Linux testbeds and supports the basic functionalities for a future implementation of the signaling plane.

ABSTRACT
This work focuses on the analysis of Quality of Service (QoS) management in controlled scenarios such as corporate networks. We present a testbed based on BGP/MPLS IP VPN networks and show the QoS configuration implemented in the different nodes. The motivation of this work is to obtain stable QoS monitoring procedures that will allow us to deploy optimized QoS management mechanisms. The results are intended to represent users’ satisfaction for different networked services, so we base our QoS evaluation in perceived-QoS (PQoS) schemes. In this paper we proposed a network scenario made up of a VPN connectivity between two corporate sites. Based on the terms included in the SLA and the characteristics of different traffic profiles, we try to monitor the PQoS in different conditions, so we can obtain valuable information for a better traffic classification.

ABSTRACT
Traditional QoS related studies handle technical KPI (key performance indicators) which are supposed to measure the quality of telecommunication services. However, while trying to select an ISP, most users are not able to choice the most suitable one for their needs. This papers presents the application of a perceived QoS based model as a tool for helping users in this kind of decisions. Our model represents the impact of each one of the objective performance indicators on the perception of quality for a particular user profile. Once the model is built common users will be able to identify the best combination of performance indicators for their pattern of use of the different Internet services. We have used velocimetro.org, a website that provides measurement services for common users, in order to feed the model with real world values and compare 4 different Spanish ISPs.

ABSTRACT
Data network Quality of Service (QoS) measurement and evaluation is a challenge being deeply studied nowadays. Measurement techniques and methodologies are broad available, but they are not connected among them, this is, the evaluation is based on raw parameters. In this paper we present a proposal of an integrating architecture which can evaluate user's perceived QoS, merging results obtained by different measurement tools in order to acquire a better knowledge of the communication link than using a single parameter. Extra effort is made to develop a set of easy to use and understand measurement tools.

ABSTRACT
This paper deals with the management of QoS as perceived by end users in corporate networks. First, we overview some previous results achieved by the research group in the field of estimating and managing the QoS. In this work we accomplished some validation tasks by means of simulation. Going on with the analysis of applicability of the general model to real-world, we propose here to analyze a network scenario that includes an MPLS IP VPN. In this scenario we can take into account all the agents involved in the provision of Internet services and moreover we can carry out a management of QoS in the network.

ABSTRACT
In last years there have been some governmental initiatives aimed at the regulation of quality of service evaluation in telecommunications services. However this has proven to be a complex task especially for Internet services, where it is difficult to objectively assess the quality of a service and to identify whether one or more of the provider agents are responsible of final dissatisfaction of users. This paper affords the cited problem and intends to provide a methodology to asses the quality of service as perceived by end users. The aims of the proposed model are twofold: the evaluation of perceived quality of service (PQoS) based on subjective and objective measurements and the identification of responsibilities of the different agents involved in a service provision.

ABSTRACT
This paper presents a comprehensive model intended to analyze quality of service in telecommunications services and its causes. Although many works have been published in this area, both from a technical viewpoint as well as taking into consideration subjective concerns, they have not resulted in a unique methodology to assess the experienced quality. While most of the studies consider the quality of service only from a technical and end-to-end point of view, we try to analyze quality of service as a general gauge of final users' satisfaction. The proposed model allows us to estimate the quality experienced by end users, while offering detailed results regarding the responsibility of the different agents involved in the service provision. Once we overview the most significant elements of the model, an in-depth analytical study is detailed. Finally, we illustrate a practical study for web browsing service in order to validate the theoretical model.

ABSTRACT
This paper proposes a service descovery protocol for discovering and advertising services in a proactive ad hoc network. The protocol we have defined is piggybacked into the OLSR (Optimized Link State Routing) routing protocol. We have defined a new message type into OLSR, called Service Discovery Message (SDM), for both advertisement and discovery of services. The advertisement frequency and advertisement lifetime are user-controlled parameters, so that they can be modified depending on the user requirements. Each node mantains a service cache to store information about its own services, and the services each device discovers in the network. We also present simulation results of our protocol and show that the service discovery protocol defined here, achieves much efficiency in discovering services, while it introduces practically no packet overhead compared to the basis OLSR protocol.

ABSTRACT
One of the most important tasks of a researcher consists in performing tests to validate the results of the research done. In a network related research work, with complex infrastructure and many configuration parameters, testing our work is usually rather mechanic, tedious and error prone if tests are done manually. In the Networking, Quality and Security Research Group, we have developed a generic test framework to automate this important task, composed of four kind of logical elements: a manager, agents, daemons and formatters. With these four elements, every phase of the process is automated, from test configuration to result formatting. The deployment of this framework has drastically reduced the time needed for the test phase and the number of errors due to mistakes. It has also allowed us to share resources among projects more easily and to schedule test sets when the devices are not being used.

ABSTRACT
This paper presents a comprehensive model intended to analyse general quality in telecommunications services centred in end users’ perceived quality (PQoS). The proposed model allows us to estimate the quality experienced by end users, while offering detailed analyses regarding the responsibility of the different agents involved in the service provision. We overview the structure of the model, that resembles QFD general quality model. Then we describe a practical study where the variation of the global satisfaction of users is estimated. This approximation is carried out by means of the evaluation of a set of telecommunications services with diverse nature, such as web browsing, VoIP and even technical support. Finally, we use the multiple linear regression method for assessing different providers' contribution to the PQoS in every considered network state.

ABSTRACT
This paper proposes a service discovery protocol for discovering and advertising services in a proactive ad hoc network. The protocol we have defined is piggybacked into the OLSR (Optimized Link State Routing) protocol. We define a new message type into OLSR called Service Discovery Message (SDM) for both advertisement and discovery of services. The advertisement frequency and advertisement lifetime are usercontrolled parameters, so that they can be modified depending on the user requirements. Each node maintains a service cache to store information about its own services, and the services each device discovers in the network. We also present simulation results of our protocol and show that the service discovery protocol defined here achieves much efficiency in discovering services, while it introduces practically no packet overhead compared to the basis OLSR protocol.

ABSTRACT
This paper analyses several issues about security and QoS in corporate networks based on BGP/MPLS IP VPN technology. First, we discuss some security requirements and constraints specified for ‘conventional’ BGP/MPLS IP VPNs, where the provider’s transport infrastructure supports MPLS. Likewise, we describe different alternative mechanisms suitable to provide QoS guarantees in this kind of networks. Afterwards, the paper focuses on a transition scenario, where some of the corporate sites may be attached to an IP backbone with no MPLS support. In order to preserve the basic VPN architecture some alternative tunneling approaches are defined. We study some critical security requirements in this scenario and analyse the potential impact of its implementation over the QoS characteristics. We present a testbed based on Linux boxes and some general implementation issues, and finally some empirical results are shown.

ABSTRACT
In this article, we introduce a tool to analyse quality of service in DiffServ-MPLS networks and we also show its design and implementation issues. We have designed a distributed architecture that allows users to send and receive traffic flows in real-world environments applying several service policies, extracting quality of service parameters from end hosts and core devices, and information about performance in traffic flows treatment at DS-MPLS network core nodes.

ABSTRACT
The current expansion of new services, which require high bandwidth rates, has enforced an increase of network throughput hindering network monitoring. Conventional network traffic analysis tools like tcpdump or ethereal were not designed to keep up with new rates so loss rates are very high. Consequently, we have developed a sensor that exploits multiprocessor features in order to reduce loss rates in high speed networks. Most network traffic analysis require communication among instances yielding synchronization troubles that must be solved. As the sensor splits traffic analysis loads among different processes, they will concurrently access to shared memory areas. Conventional synchronization mechanisms like semaphores are not a good approach because they harm sensor’s performance highly. Hence, in this paper we introduce a number of mechanisms that improve the overall performance of the sensor as a result of an effective communication among instances.

ABSTRACT
As networks become faster, traffic analizers and network intrusion detections systems have big problems handling all the traffic of a network. As a result of the investigation on this topic, looking for parallelism in the processing of the captured traffic, this document presents a tool designed for high-speed network traffic analysis. The tool is based on the concurrent analysis of multiple instances, using shared memory as an interface among instances and between modules of the system. The system includes a powerful rule language with adds big flexibility to the system, and so the tool may work in different areas involving traffic analysis, including both for Intrusion Detection System (IDS) and Quality of Service (QoS) analysis.

ABSTRACT
The development of enterprise web applications is a very complex and multi-part issue where different programming technologies and tools have to be used. Although these specialized technologies and tools are intended to work together, it would be desirable to have a very flexible designing and developing framework where all the information was managed and stored following a predefined Service Driven Architecture which should also provide internationalization (i18n) to web pages for content and presentation. XML technologies and Java based web applications (implemented as a component-based multi-tier application design defined by J2EE) have been selected to put into practice that kind of framework. This paper describes the nature of enterprise web applications, proposes a service-based approach to develop these systems and presents an example where this solution is used to fulfill the internal management needs of a university department.