Regina Melo Silveira

Multipath source routing strategies for video transmission in ad hoc wireless networks

AbstractEmploying multipath routing with video transmission can improve reliability and end-to-end delay. Many prior works investigate this combination in the scenario of wireless ad hoc networks, considering that at least two paths can be found. Nevertheless, the number of available paths is highly dependable on network topology and density. Thus, link-disjoint paths may not be available at a number large enough for exploring path diversity. A path selection strategy over source routing is proposed that makes the concept of disjointness more flexible, providing the quasi-disjoint paths (QD-paths). In order to compare our scheme with prior work, we also adapt a multipath routing protocol, namely SMR, for using disjoint-paths (D-paths) with a method of greedy path selection and round-robin schedule. Simulation results demonstrate that QD-SMR and D-SMR have much better results than standard SMR. The main result is that QD-paths increase path diversity with low overhead, which improves redundancy.

PCE algorithm for traffic grooming and QoS in multi-layer/multi-domain IP over WDM networks

Differentiated services provision according to clients or applications is an added feature that network operators ambition to fully provide. One of the possible approaches is to map DiffServ into MPLS based network. However in an IP over WDM (Wavelength Division Multiplexing) network data flow traverse multiple layers and, therefore, Class-Type information from the MPLS DiffServ layer is eventually lost. Besides, with the implement of a Path Computation Element (PCE) on multi-layer and multi-domain networks, the bandwidth constraints used to differentiate services are no longer applied. This paper presents a proposal for a QoS DiffServ approach applied on PCE as a traffic grooming technique for WDM core networks and the problematic involved on the application of this technology on multilayer and multi-domain networks.

OCP: A protocol for secure communication in federated content networks

Abstract Content Distribution Networks (CDNs) are networks that make intense use of caching and multicast overlay techniques for transmitting video and other stream media, a type of traffic that has been growing tremendously in the last years. To cope with this increasing demand, several telecommunications companies have been associated to create federated CDNs (FCDNs), that involves many different providers and, hence, distinct domains. Although beneficial in terms of increased capillarity and scalability of service delivery, the interaction between FCDN elements from different providers brings many new challenges. Among them, one that has received little attention so far refers to security, an essential service for preventing the misuse of the FCDN resources. Aiming to tackle this issue, this paper presents the Overlay Communication Protocol (OCP), a security mechanism that allows the secure signaling communication in FCDNs. OCP takes into account all elements involved in the content delivery process, addressing Route Forgery attacks and concealing the network structure from potential attackers. Together with the protocol description and security analysis, we also present experimental results on its implementation, showing that it introduces little impact on the overall network performance.

Challenges and Requirements of a Control Plane for Elastic Optical Networks

Elastic Optical Networks have emerged as a promising technology for the e cient use of optical network resources. Its adaptable characteristics and adjustable data rate enable operators to meet the diverse granularity of their clients needs. In order to automate an elastic optical network operation, a control plane is required. Wavelength Switched Optical Networks (WSON) may already rely on a robust control plane which enables dynamic network management, provides prompt demand reply optimizing spectrum use, and implements important network features as survivability strategies, di erentiated service, and grooming procedures. Due to its specific characteristics, Elastic Optical Networks may not implement traditional WSON control plane solutions without further enhancement. Therefore, recent research e orts have been focusing on developing the control plane for this new technology, in most cases by proposing extensions to the currently available architectures. This paper describes a survey on the current ongoing research e orts to define Elastic Optical Network control plane architecture. It identifies and classifies the most relevant proposals currently found in literature, and discusses how these propositions address the main requirements to design a control plane which enables automating the specific functions of an Elastic Optical Network.

Integrating MPEG-7 descriptors and pattern recognition: an environment for multimedia indexing and searching

This paper describes a music searching system based on an automatic indexing process created over a pattern recognition tool and MPEG-7 standard. We present a complete analysis of the involved technologies integration process and show a reference measure in the feasibility of this kind of application not only in the research environment but also in the production of real systems.

An Overlay Application-Layer Multicast Infrastructure

Overlay networks are considered an easy and effective way to deploy value-added Internet services by extending the best-effort delivery service supported by IP layer. However, a careful design is needed in order to take advantage of these benefits. Since there are no standards for overlay networks yet, they are often independently designed, which means that each one applies its own topology discovery and takes its own routing decisions. As a result, they may negatively affect each other by generating control overhead and by creating bottlenecks in the physical network. In order to avoid such a situation, this work proposes an overlay network organization and architecture towards a middleware for overlay multicast services. As proof of concept, we have deployed a multicast service overlay network taking advantage of this architecture and considering both intradomain and interdomain scenarios – the latter being practically impossible to deploy on public networks due to administrative issues. By experimental measurements, we validate interdomain multicast functionality over four autonomous systems without any native support from underlying networks.

NetLab: A Framework for Remote Network Experiences

This work presents some results in the construction of a framework to provide distant network experiences. This framework, called NetLAb, will offer all network experiences of our regular undergraduate course at de Computer Engineering course at Politechnic School of Sao Paulo University in a virtual way to regular students and students of other correlated courses

Evaluating the effectiveness of the use of teaching materials in video format in distance learning environments

Projections indicate that video will be responsible for 90% of network traffic until the end of the decade. Considering the high cost of media production and, mainly, the high consumption of network resources for applications that explore it, it will be extremely important to monitor such use, preventing against wrong or distorted views of this consumption. Within this scenario, it is necessary to develop mechanisms and tools that provide a clear vision of video effectiveness consumption, as well as the measuring of “viewer engagement”. What tools can be developed to evaluate such consumption? What should be measured, i.e., which are the parameters and metrics necessary, and how can we obtain them, in order to measure the effectiveness of video applications use, for example in engineering courses and distance learning environments? These are some of the questions considered in this paper, especially evaluated within a scenario of video usage for teaching/learning purpose.

Fiber-based testbed architecture enabling advanced experimental research

In 2005, the creation of the network for the Kyatera project began, with the declared goal of designing the most advanced and innovative research and experimental network of Latin America. This paper describes the groundwork for the development of such network in terms of its requirements, functionalities, provided services, enabled researches and design concepts. Structurally, the Kyatera network is composed of three sub-networks that will enable parallel experiments and research to be carried out in optical, networking and applications domains. Given the services and the technologies deployed, it will promote the development of joint experiments with peer advanced research centers both national and international

An environment for easy cross synchronization of multimedia Web based material

The use of Web based content presentations as an information exposure method is essential for the online learning process. Our main goal is to present the main functional specifications of an easy-to-use tool for creating Web based cross-synchronized multimedia presentations.