Relay nodes act as L1 caching layer and come in the layer between master nodes and viewers. Although their storage capacities and uptime guarantees aren’t as strong as the master nodes, they are present at a higher density than the master nodes and are closer to the viewers.
Master nodes present in the region decide the specific resources relay nodes should store based on the popularity, resource size, and other considerations. A master node can optionally act as a relay node too.
Master nodes have high storage and bandwidth facilities and act as L2 caching layer. Commercial data centers with spare capacity or entities who buy high capacity hardware specifically for the purpose of being a CDN node can be a master node.
Master nodes guarantee availability and persistence of data. They also decide global resource allocation by applying machine learning models over resource demand patterns. They efficiently route requests to relays so that the clients can fetch resources from his closest nodes.
Blockchain nodes and Miners handle the payment processing and fraud analysis in the Marlin network. They trustlessly verify the transactions to ensure that publisher is not being overpaid and serving nodes are adequately compensated.
Blockchain nodes also perform several checks on the serving nodes such as Proof of Availability, Augmented Proof of Storage-Time, to track any fraudulent behavior and ensure network’s quality of service.