Two-layer hierarchy unstructured peer-to-peer (P2P) systems, comprising an upper layer of superpeers and an underlying layer of ordinary peers, are commonly used to improve the performance of large-scale P2P systems. ...
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Two-layer hierarchy unstructured peer-to-peer (P2P) systems, comprising an upper layer of superpeers and an underlying layer of ordinary peers, are commonly used to improve the performance of large-scale P2P systems. However, the optimal superpeer network design involves several requirements including superpeer degree, network diameter, scalability, load balancing, and flooding performance. A perfect difference graph has desirable properties to satisfy the above design rationale of superpeers overlay network. This paper proposes a two-layer hierarchical unstructured P2P system in which a perfect difference graph (PDG) is used to dynamically construct and maintain the superpeer overlay topology. In addition, the broadcasting performance of the P2P system is enhanced through the use of a PDG-based forwarding algorithm, which ensures that each superpeer receives just one lookup query flooding message. The theoretical results show that the proposed system improves existing superpeer hierarchical unstructured P2P systems in terms of a smaller network diameter, fewer lookup flooding messages, and a reduced average delay, and the experimental results show that the proposed two-layer hierarchy P2P system performs very well in the dynamic network environment.
Multi-granular traffic is considered as the traffic generated by the high variety of applications supported by Future Internet. Hybrid interconnection is a viable way to achieve the high throughput and flexibility req...
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ISBN:
(纸本)9783901882418
Multi-granular traffic is considered as the traffic generated by the high variety of applications supported by Future Internet. Hybrid interconnection is a viable way to achieve the high throughput and flexibility required in the optical nodes with available optical and electronic technology. The task of finding a way to efficiently match these two key aspects is a challenge for possible short term exploitation of optical technology in dynamic networking. In this paper, multi-granular traffic representation and scheduling to exploit hybrid switch resources are proposed, while differentiating traffic classes. Loss and delay are evaluated by simulation based on a simplified ON/OFF model of the input traffic mix, which is able to take some key aspects of multi-granular traffic, such as burstiness and quality of service requirements, into account. Results outline the class isolation capabilities of the proposed scheduling algorithm and the achievements in terms of time and semantic transparency.
In this paper, we seek to improve understanding of the structure of human mobility, with a view to using this for designing algorithms for the dissemination of data among mobile users. We analyse community structures ...
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In this paper, we seek to improve understanding of the structure of human mobility, with a view to using this for designing algorithms for the dissemination of data among mobile users. We analyse community structures and node centrality from the human mobility traces and use these two metrics to design efficient forwarding algorithms in terms of delivery ratio and delivery cost for mobile networks. This is the first empirical study of community and centrality using real human mobility datasets.
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