关键词: 区块链, 点对点网络, 分叉, 传播延迟, 邻居选择

Abstract: Blockchain relies on an unstructured peer-to-peer overlay network for the propagation of transactions and blocks. In this network structure, propagation is delayed, and the long-tail propagation problem is significant, which leads to inconsistencies in the information stored by nodes, i.e., the phenomenon of blockchain forks. Forks not only waste computational resources across the entire blockchain network but also introduce a series of security issues. To reduce propagation delays in blockchain networks, a Neighbor Selection Based on Multi-stage Propagation (NSMP) is proposed, which optimizes the network topology by selecting neighbor nodes. In this scheme, nodes are divided into strong and weak propagators for their outbound neighbors based on two factors: propagation ability and proximity. Different neighbor selection schemes are applied at different stages of network propagation, thereby reducing propagation hops and shortening propagation time. This scheme further addresses the long-tail propagation problem present in both existing and default schemes. Finally, the propagation ability of nodes is quantified by fitting a function based on local node characteristics, and the proximity of nodes is quantified using the Ping protocol. The designed scheme is tested through simulation experiments using the network simulator Sim Block. Experimental results show that NSMP reduces the fork rate by 52.17% compared to the default scheme, demonstrating the feasibility and effectiveness of NSMP. Based on the simulation data, the optimal parameter settings for the distribution of neighbor node proximity are determined.

Key words: block chain, Peer-to-Peer (P2P), network, fork, propagation delay, neighbor selection