Formal reasoning on Peer-to-Peer (P2P) systems is an intimidating task. This paper focuses on broadcast algorithms for Content Addressable Network (CAN). Since these algorithms run on top of complex P2P systems, findi...
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ISBN:
(数字)9783642370571
ISBN:
(纸本)9783642370571
Formal reasoning on Peer-to-Peer (P2P) systems is an intimidating task. This paper focuses on broadcast algorithms for Content Addressable Network (CAN). Since these algorithms run on top of complex P2P systems, finding the right level of abstraction in order to prove their functional correctness is difficult. This paper presents a mechanized model for both CAN and broadcast protocols over those networks. We demonstrate that our approach is practical by identifying sufficient conditions for a protocol to be correct and efficient. We also prove the existence of a protocol verifying those properties.
We consider the problem of serving a set of sensors/end-users at multi-level quality of service. Consider for example the problem, which arises in augmented reality applications, of single-hop radio broadcasting a com...
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ISBN:
(纸本)9781509024612
We consider the problem of serving a set of sensors/end-users at multi-level quality of service. Consider for example the problem, which arises in augmented reality applications, of single-hop radio broadcasting a common content from a provider. Each end-user requires a minimal quality level of the common content. The provider must satisfy all end-users at their required minimal quality level with a point-to-point encrypted transmission. Since the number of different quality level versions of the common content cannot be as large as the number of end-users, the provider has to partition the end-users into groups. The provider adopts for each group a quality level which is the maximum among the levels required by the end-users of that group. In doing so, the provider incurs into an encryption and transmission cost which is proportional to the product between the end-user group size and the adopted quality level. Such a problem consists in finding a partition of the end-users that satisfies their requests and minimizes the overall provider cost. These quality of service problems are optimally solved in polynomial time by dynamic programming techniques for an arbitrary number of end-users. A faster greedy heuristic is also proposed which quickly finds a solution very close to the optimum one.
Blockchain technology offers an intelligent amalgamation of distributed ledger, Peer-to-Peer (P2P), cryptography, and smart contracts to enable trustworthy applications without any third parties. Existing blockchain s...
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ISBN:
(纸本)9783030192235;9783030192228
Blockchain technology offers an intelligent amalgamation of distributed ledger, Peer-to-Peer (P2P), cryptography, and smart contracts to enable trustworthy applications without any third parties. Existing blockchain systems have successfully either resolved the scalability issue by advancing the distributed consensus protocols from the control plane, or complemented the security issue by updating the block structure and encryption algorithms from the data plane. Yet, we argue that the underlying P2P network plane remains as an important but unaddressed barrier for accelerating the overall blockchain system performance. Our key insights from comparative assessments reveal the fact that P2P topology highly affects the broadcast speed of blockchain data, leading to poor performance and vulnerable to double spending attacks. In this paper, we introduce BlockP2P, a novel optimization design to accelerate broadcast efficiency and meanwhile retain the security. BlockP2P first operates the geographical proximity sensing clustering, which leverages K-Means algorithm for gathering proximity peer nodes into clusters. It follows by the hierarchical topological structure that ensures strong connectivity and small diameter based on node attribute classification. We finally propose the parallel spanning tree broadcast algorithm to enable fast data broadcast among nodes both in the intra- and inter- clusters. To clarify the influence of each tier, we carefully design and implement a blockchain network simulator. Evaluation results show that BlockP2P can exhibit promising performance compared to Bitcoin and Ethereum.
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