Investigating Layer-2 Scalability Solutions for Blockchain Applications

Scalability is one of the trilemma of blockchain technology that hinders its adoption for large-scale decentralized applications (dApps). Researchers have proposed several layer-1 and layer-2 solutions to address the issue. This paper focuses on layer-2 solutions or protocols operating on top of the primary blockchain to enhance scalability. Previous works surveying these solutions mainly focused on a particular layer-2 solution, like rollup, or a specific application, such as smart manufacturing. However, in this paper, we present a comprehensive analysis of layer-2 scalability solutions, such as state channels, side-chain, and rollup, from the perspectives of various functional requirements of block chain applications. More precisely, the goal is to evaluate the applicability of the layer-2 scalability solutions in terms of the application patterns that depict the transactional dependencies, interoperability, decentralization, and security. To further illustrate these features, the paper evaluates the applicability of the layer-2 solutions on the case studies of major blockchain applications, including supply chain management and healthcare. Our analysis suggests that in terms of throughput, application pattern is the most crucial aspect in selecting the scaling solutions, in conjecture with other features as per the application demand.