At the core of each blockchain system, parties communicate through a peer-to-peer (P2P) overlay. Unfortunately, recent evidence suggests these P2P overlays represent a significant bottleneck for transaction throughput and scalability. Furthermore, they enable a number of attacks. We argue that these performance and security problems arise because current P2P overlays cannot fully capture the complexity of a blockchain system as they do not offer flexibility to accommodate node heterogeneity. We propose a novel approach to address these issues: P2P Overlay Domains with Sovereignty (PODS), which allows nodes in a single overlay to belong to multiple heterogeneous groups, called domains. Each domain features its own set of protocols, tailored to the characteristics and needs of its nodes. To demonstrate the effectiveness of PODS, we design and implement two novel node discovery protocols: FedKad and SovKad. Using a custom simulator, we show that node discovery using PODS (SovKad) architecture outperforms both single overlay (Kademlia) and multi-overlay (FedKad) architectures in terms of hop count and success rate, though FedKad requires slightly less bandwidth.

翻译：在区块链系统的核心，各参与方通过点对点（P2P）覆盖网络进行通信。然而，最新证据表明，这些P2P覆盖网络已成为交易吞吐量和可扩展性的显著瓶颈，并导致了多种攻击。我们认为，当前P2P覆盖网络无法充分适应节点异构性，因此不能完整反映区块链系统的复杂性——这正是性能和安全问题的根源。为此，我们提出一种新方法：主权P2P覆盖域（PODS），允许单一覆盖网络中的节点归属于多个异构组（称为域）。每个域拥有针对其节点特征和需求量身定制的协议集。为验证PODS的有效性，我们设计并实现了两种新型节点发现协议：FedKad和SovKad。基于自定义模拟器的实验表明，采用PODS架构（SovKad）的节点发现在跳数和成功率上均优于单覆盖网络（Kademlia）和多覆盖网络（FedKad）架构，尽管FedKad的带宽消耗略低。