Đang chuẩn bị liên kết để tải về tài liệu:
Resource Management in Satellite Networks part 12

Resource Management in Satellite Networks part 12. This book provides significant knowledge on innovative radio resource management schemes for satellite communication systems that exploit lower layer adaptivity and the knowledge of layer 3 IP QoS support and transport layer behavior. The book integrates competencies considering all the parts of system design: propagation aspects, radio resource management, access protocols, network protocols, transport layer protocols, and more, to cover both broadband and mobile satellite systems | 90 José Ignacio Moreno Novella Francisco Javier Gonzalez Castaño and to the access part and the users terminals via the Access Routers. The core network hosts two servers supporting different functionalities of NGNs. These functionalities include aspects that should be present in next-generation commercial mobile networks such as user authentication and accounting mobility and QoS management were also controlled by these servers. All the nodes including the routers are general-purpose machines Pentium III and IV PCs . All run Red Hat 7.2 with Linux-2.4.16 kernels. More details about the test bed can be found in 30 . QoS is based on DiffServ with access control. This access control is performed on the Access Routers on a per flow and per user basis. The Access Router outsources the admission decision to the QoS broker an entity located in the core network able to take this decision and configure the routers with appropriate parameters. The test bed here described is composed of general-purposes machines and it is just a mere representation of what a next network infrastructure may be but we believe that the results obtained in it can provide us early and valuable hints about the applications specific QoS requirements when using NGNs. We performed on-site real measurements of end-user performance perception and application characterization under different situations that can be present in NGNs as detailed in 30 and 31 . The tested applications correspond to conversational services and interactive services. All of them were IPv6 applications. Conversational services were provided by Robust Audio Tool RAT for conversational voice and Quake 2 and Tetrisnet for games. Again for interactive services we employed RAT for audio streaming and VideoLan for video streaming. Conversational and interactive services characterization was already described in Section 3.2 the added value of this Section is to show experimental studies obtained in an NGN prototype and check the .