2.2 Structural Comparison of P2P and P2M Transaction Networks
Analyzing the operational topology of the Unified Payments Interface (UPI) reveals profound structural asymmetries between peer-to-peer (P2P) and peer-to-merchant (P2M) settlement channels. As documented in empirical evaluations of transaction trends across payer and payee payment service providers, P2M interactions exhibit dense star-like hub formations characterized by unidirectional high-frequency inflows toward accredited merchant nodes, whereas P2P exchanges generate diffuse, multi-hop subgraphs across decentralized retail accounts (Analysis of Unified Payments Interface, 2025). When mapping financial fraud typologies onto these topological configurations, conventional machine learning models that evaluate transactions as isolated tabular instances fail to identify adversarial graph distortions, such as cyclical layering or mule account dispersion (Unified Payments Interface Fraud Detection Using Machine Learning, 2025). In contrast, applying relational graph modeling exposes distinct anomaly signatures across each structural class. P2P fraud mechanisms rely predominantly on rapid sequential fund transfers through synthetic identity chains, requiring multi-hop neighborhood aggregation to uncover intermediate aggregator vertices before settlement finality (Unified Payments Interface (UPI): Fraud and Prevention Strategies, 2025). Conversely, fraudulent infiltration within P2M topologies manifests through sudden structural anomalies in node degree centrality, such as unauthorized spoofing or atypical outbound disbursements from purported terminal merchant nodes. Embedding relational graph architectures into real-time surveillance frameworks enables payment operators to isolate benign commercial hub dynamics from coordinated adversarial networks, establishing a robust basis for context-aware risk scoring.