1,720,960 research outputs found
SRDP-Sign: a reliable multicast protocol for signaling
No full textIn this paper we present SRDP-sign, a reliable multicast protocol designed to guarantee the reliable transmission of short messages via satellite as an extension of satellite reliable distribution protocol (SRDP). The uses of this protocol range from sending short text messages to transmitting information used for the improvement of networkspsila performances. The innovation of this protocol is that it has a high degree of scalability, reduced communication with receivers and fast delivery. In this paper we show the operations of the protocol, the underlying algorithms and analyse the protocolpsilas behavior
Reliable Key Distribution for Secure Multicast by SRDP-Sign
No full textSecurity is an important concern in today's networking and particularly in satellite communication, where eavesdropping and active intrusion is much easier than in terrestrial fixed or mobile networks because of the broadcast nature of satellites. Many applications require the security feature of data confidentiality; in order to offer such capability, encryption keys must be constantly changed upon a membership change. If the keys are sent via multicast, that it is particularly useful for large groups, reliable multicast is required. In this paper we propose an efficient, reliable and multicast distribution of the encryption keys with SRDP-Sign (Satellite Reliable Distribution Protocol for Signaling). We guarantee reliability for all the receivers with a high degree of scalability. Total reliability error and the overall latency in the key distribution will be evaluated
Fast re-establishment of QoS with NSIS protocols in mobile networks
No full textRe-establishment of the QoS after a Mobile Node handover must be done as quickly as possible in order to reduce degradation or interruption of QoS, especially when realtime applications are used. We propose a Semi-Proactive procedure for a faster QoS re-establishment in environments where there are Mobile Nodes. The basic functionality of this procedure is to perform as many operation as possible before the handover (in a proactive manner). Resources are reserved after the handover on the effective new data path in order to avoid their waste. Moreover, we propose to buffer at the Candidate CRossover Node - CCRN (an intermediate node on end-to-end data path) the packets directed to the Mobile Node during the handover. In this way the total QoS re-establishment time is reduced. This buffering also guarantees the same QoS treatment of both the buffered and the non-buffered packets
Multicast Security and Reliable Transport of Rekey messages via satellite
No full textThe problems involved in multicast key distribution are discussed. Three protocols to accomplish such task are presented (one of them being designed by the authors) and their performances are compared
CHARMS: Cooperative Hybrid Architecture for Relaying Multicast Satellite Streams to sites without a satellite receiver
No full textThe paper describes an architecture dedicated to the terrestrial relaying of a real-time IP multicast audio-video stream broadcasted by a satellite. Such relaying is performed by nodes equipped with both a satellite receiver and a terrestrial Internet link. The stream is requested and obtained by sites that are not equipped with satellite receiving hardware but are nonetheless willing to receive it. By exploiting the properties of satellite transmission and adopting an hybrid satellite/terrestrial, multicast/unicast approach the described architecture allows to overcome the restrictions suffered by multicast traffic in the global Internet, allowing it to scale easily across autonomous systems
The Campus Satellitare del Salento: A Large-scale Satellite Distance e-Learning Trial
No full textThe Campus Satellitare del Salento (CSS) will be presented in this paper. The CSS is a platform for developing and delivering e-learning services and is useful to address problems arising from teaching large classes of learners distributed throughout a wide geographic area. This paper will describe the CSS platform and issues related to a specific trial application
A new approach for Hybrid Satellite-Terrestrial Networks: cooperative architecture to relay multicast satellite streams
No full textThe broadcast properties and the wide coverages of the satellite are ideal for multicast applications.
Unfortunately among the satellites most domestic parabolas are aimed at are not the less expensive ones. To overcome this problem we propose in this paper a relaying architecture where the sites equipped to receive the satellite transmission become relayers of the received multicast flows on the terrestrial Internet to the benefit of the sites which are not equipped with a satellite receiver. Also, this is done recursively, that is, the sites getting the flows will help to propagate them further.
This architecture allows to overcome the restrictions suffered by multicast traffic in the global Internet
Semi-Proactive RSVP extension for wireless mobile networks
No full textMobility and quality-of-service (QoS) management are important tasks for the future development of wireless networks. The RSVP model, which is efficient in resource reservation at the fixed endpoints, becomes invalid under host mobility. In this article we focus on how quality of service guarantees can be provided for the RSVP flows during the handover events. We propose to perform as many operation as possible before the handover but the resources are reserved only after the handover on the effective new data path, in order to avoid their waste. We refer to it as a semi-proactive extension to the RSVP protocol. In order to reduce much more the time used for re-establishing the proper QoS, we propose to buffer at the candidate crossover node - CCRN (an intermediate node on end-to-end data path) the packets directed to the mobile node during the handover. This buffering also guarantees, for the buffered packets, the same QoS treatment of the no-buffered one
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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