Luis F. Faina

An agent-based approach for supporting quality of service in distributed multimedia systems

Quality of service (QoS) is a core issue in multimedia systems. Intuitively, QoS states how valuable the services provided by a multimedia system are. As a rule, QoS is established through negotiation between users and service providers. The negotiation involves allocation and management of resources in order to attend an expected level of quality. The process of negotiation is simple if the resources are managed by a single entity (e.g., operating system) or by a set of entities supporting a common negotiation protocol. Unfortunately, in distributed multimedia systems, negotiation and management of resources are complex tasks since resources are diversified, distributed and managed by autonomous entities. In order to minimise such difficulties, an agent-based architecture for QoS negotiation and management in distributed multimedia systems is proposed in this paper. The proposed architecture combines fixed and mobile agents that interact among themselves with the aim of establishing and maintaining a certain level of QoS. This paper also presents the current implementation stage of the proposed architecture.

QoS agency: an agent-based architecture for supporting quality of service in distributed multimedia systems

The quality of service (QoS) is a core issue in multimedia systems. Intuitively, the QoS states how good the services provided by a multimedia system are. As a rule, the QoS is established through negotiation between users and service providers. The negotiation involves allocation and management of resources in order to attain a desired level of quality. Examples of such resources are peripherals, CPU, network bandwidth, data formats and synchronization levels. The process of negotiation is simple if the resources are managed by a single entity (eg. operating system) or by a set of entities supporting a common negotiation protocol. Unfortunately, in distributed multimedia systems the negotiation and management of resources are far from being simple tasks since resources are diversified, distributed and managed by different entities. In order to minimize such difficulties, an agent-based architecture for QoS negotiation and management is proposed. The architecture combines fixed and mobile agents that interact with the aim of establishing and maintaining a certain level of QoS in a distributed multimedia system. This paper also describes a partial implementation of the proposed architecture using well accepted standards such as CORBA (Object Management Groups Common Object Request Broker Architecture), RTP (Internets Real Time Protocol), products like Aglets Workbench (a Java based mobile agent framework from IBM) and the Orbix family from Iona.

A Web Lab for Mobile Robotics Education

This paper presents an architecture for building remote access laboratories (or Web labs) following the service-oriented computing approach. In this architecture the applications building blocks are services that can be recursively composed resulting in more comprehensive services. Remote access laboratories can benefit of this approach. Every lab resource (physical or logical) is modeled and implemented as a service (in our case, a Web service) and lab experiments are assembled by composing these services. A Web lab built according to this architecture is presented with examples of remote experiments in the field of mobile robotics.

Performance analysis of XOR-based routing in urban vehicular ad hoc networks

This paper presents the URBAN_XOR1 protocol, an XOR-based flat routing mechanism developed for vehicular ad hoc networks (VANETs) formed in urban scenarios. The paper firstly describes the URBAN_XOR routing principle, which requires reduced knowledge about the set of nodes present in the VANET in order to provide traffic forwarding. Basically, the URBAN XOR protocol introduces the concept of local visibility, prioritizing the insertion of closer neighbors (in number of hops) in the routing tables, and simplifying the management of the frequent network mobility found in VANETs. Then, the performance of the proposed URBAN_XOR protocol is compared through simulation with other topology-based and position-based protocols, characterizing its performance in terms of path availability ratio, end-to-end delay, path length and path duration. The results reveal that URBAN_XOR contributes for the overall network stability, reducing the end-to-end delay due to its ability of generating shorter paths. At the same time, URBAN_XOR exhibits path availability similar to other topology-based protocols, but exhibiting better path duration times.

An Architecture for Traffic Sign Management in Smart Cities

This paper introduces and evaluates a Traffic Sign Management Architecture (TSMA), which represents a paradigm shift for the deployment of traffic sign infrastructure in the context of Intelligent Transport Systems, Vehicular Networks and Smart Cities. The proposal addresses limitations of the current traffic control model by enabling remote updates of traffic signs and displaying them on the vehicular navigation system display to improve their legibility. TSMA is an architecture developed to provide V2I interaction using a commodity technology, Wi-Fi, through the beacon-stuffing technique. The initial design of TSMAs security mechanisms is also presented in this paper. Evaluations were performed on a developed prototype and simulation environments.

An Architecture for Monitoring and Improving Public Transportation Systems

Brazilian public transportation systems are facing a significant demand reduction, mainly due to the poor quality of the offered services, lack of information regarding lines and timetables, high cost and lack of investment from the government. Even though it is not trivial to improve financial aspects related to the public transportation system, this work claims that the overall system quality can be improved through ubiquitous data collection according to a proposed ontology, which is the basis for knowledge extraction to support the required quality of experience improvements. The proposed architecture relies on standard technologies available nowadays, providing a low cost solution for the required data collection and analysis. This paper presents the proposed inter-networking architecture and ontology, then evaluates the system performance using a prototype developed with standard solutions.

A Platform for Monitoring Service-Level Metrics in Software Defined Networks

This paper presents and evaluates a platform for monitoring service-level metrics in OpenFlow Software Defined Networks (SDN), named SDNMon. The platform supports frequent network observation, at different granularity levels, including per-flow observation, being able to present accurate on-the-fly statistics regarding throughput and delay. The evaluation considered two statistical data gathering approaches, a proposed polling-based mechanism which collects information kept by OpenFlow counters at the network elements, and an alternate sampling-based mechanism which uses sFlow.

ASN-FWD: Shrinking the IPv4 Share on the Forwarding Information Base

This paper presents a proposal for shrinking the number of IPv4 FIB (Forwarding Information Base) entries required on routers. Traffic forwarding under the proposed mechanism is based on the current ASNs (Autonomous System Numbers), and can be gradually adopted by ISPs.We find that, at the cost of adding 8 bytes per packet, the proposed ASN-FWD technique is capable of providing full IPv4 traffic forwarding based on ASN information, which is correspondent to 10% of the current number of IPv4 prefixes present on FIB of routers. Among its main benefits, the proposed approach alleviates the pressure on the amount of FIB shipped on routers, and paves the way for a worldwide adoption of IPv6.

Node Position Forecast in MANET with PheroCast

In mobile ad hoc networks (MANET) nodes are free to move on the environment and interact with each other and with the infra-structure, enabling a multitude of applications and services. However, the same mobility that is key to MANET is also the greater limiting factor in the quality of the services provided in this environment, since the infrastructure must keep adapting to the mobility. This paper describes algorithms for predicting the future position of mobile nodes in MANET, allowing the infrastructure to proactively adapt. Our algorithms maintain the recent movement history of nodes in a compact representation, a graph, based on stigmergy of ant colonies. Predictions are generated through a limited depth first search. We have experimented this method against real world data and the results show that the prediction is accurate for short time horizons (30 seconds) in a metropolitan area (Seattle) divided in a grid of two or three-block square cells, in 77.8% of the cases. This method may be used in optimizing MANET and enabling novel applications, for example, proactive hand-off, tailored content generation, and proactive routing.

A TINA-based Distributed Environment for Mobile Multimedia Applications

This paper describes the design and implementation of a component of the Telecommunications Information Networking Architecture (TINA): the Distributed Processing Environment (DPE). TINA provides concepts, principles, models and standards for the next generation of telecommunication services. These new services take advantage of modern technologies such as high speed networks, multimedia processing, distributed objects, and component-oriented software development. The goal is to devise services that can be introduced, modified and withdrawn as soon as market demands are identified. TINA DPE provides the infrastructure necessary to distribute the service components among service users, providers and retailers. Our DPE implementation offers two basic facilities to the TINA applications: life-cycle and stream facilities. Life-cycle facilities allow distributed objects be deployed and managed transparently, while stream facilities allow application objects to exchange media flows such as audio and video flows.