NoC transaction, transport, and physical layers
Efficiency through separated NoC layers
Traditional on-chip interconnects intermingle the transaction, transport, and physical layers of communication. This can make it difficult to incorporate design changes, maintain scalability, or implement advanced features, such as QoS, power and clock domains, and security. As SoCs grow in complexity, layer separation becomes a key enabler for performance, flexibility, and predictable physical design.
Transaction layer
In the Arteris network-on-chip (NoC) architecture, the transaction layer is managed by network interface units (NIUs). These NIUs communicate directly with connected IP blocks and translate traditional AMBA, OCP, or proprietary protocol load, and store transactions into packetized data for transport across the NoC.
Because NIUs contain the majority of the interconnect logic and sit close to their associated IP cores, the transport fabric itself requires fewer gates. This helps reduce placement complexity, improves physical convergence, and simplifies interconnect verification.
Transport layer
The transport layer handles packets exclusively. Only minimal information from packet headers is needed to determine routing and switching operations. Since the transport layer does not need to interpret higher‑level transactions, its hardware remains simple, fast, and highly optimized.
With independent and modular transport components, packet routing can occur without global control. Specific routing paths can be optimized locally without affecting the overall NoC. QoS, bandwidth guarantees, and traffic priorities are implemented through packet-handling mechanisms within this layer.
Physical layer
The physical layer defines the actual transmission of packets between NoC components. Multiple link types may be used depending on distance and performance needs, including standard transport links, globally asynchronous / locally synchronous (GALS) links or chip-to-chip interconnects for multi-die systems.
Because the physical, transport and transaction layers are separated, link characteristics can change without impacting higher layers. Point-to-point connections eliminate large fan-out nets, improving timing, performance, and routing efficiency.
Benefits of separating NoC layers
- Greater modularity and easier SoC modifications
- Simpler routing and fewer global wires
- Higher achievable operating frequencies
- Improved QoS, security and clock/power domain management
- Fully pipelinable elements for predictable timing closure
In summary
Separating NoC transaction, transport and physical layers enables scalable, high-performance and flexible SoC design. Arteris NoC technology delivers simpler routing, easier timing closure, modular construction and stronger support for QoS, clocking strategies and multiprotocol IP integration compared to monolithic interconnect designs.
Learn more and explore Arteris solutions
Arteris FlexNoC® Interconnect IP
