This layer defines the logic. It knows that a ReadShared means "I want data to read, but I'm okay if others also have it." It doesn't care about wires; it only cares about messages.
The Three Layers of CHI
To handle complexity, CHI is divided into layers, similar to how the Internet (OSI model) works.
1. Protocol Layer (The Brain)
2. Link Layer (The Post Office)
This layer packages the messages into Packets and Flits. It also handles Flow Control (Credits) to make sure the receiver doesn't get overwhelmed.
3. Physical Layer (The Wires)
This is the actual electricity moving through wires on the silicon. It defines the clocks, the signals, and the physical connection between nodes.