Time-Sensitive Networking (TSN)

The foundational profile of the IEEE 1588 Precision Time Protocol (PTP) for TSN. It establishes a grandmaster clock and distributes a precise global time reference across all network nodes. This is a prerequisite for all other TSN mechanisms.

• Achieves sub-microsecond synchronization accuracy.
• Uses a Best Master Clock Algorithm (BMCA) to dynamically select the most accurate clock source.
• Enables coordinated execution of distributed control loops across a factory floor.

The Time-Aware Shaper (TAS) that enables true determinism. It divides communication into repeating cycles and creates a protected time window for time-critical frames.

• Gates at the egress port open and close according to a pre-calculated Gate Control List (GCL).
• Prevents low-priority traffic from delaying a high-priority control packet by a single microsecond.
• Essential for hard real-time applications like motion control and safety interlocks.

A mechanism to minimize the latency of express traffic by pausing the transmission of a non-critical frame mid-stream. An express frame can interrupt a lower-priority frame, and the interrupted frame resumes after the express transmission completes.

• Reduces the guard band required before a scheduled window.
• Increases bandwidth efficiency by packing more data into the cycle.
• Operates at the MAC layer, requiring hardware support on the physical interface.

The configuration model that defines how end-stations and bridges negotiate resources for a TSN stream. It moves beyond the original SRP to support fully centralized network management.

• Centralized Network Configuration (CNC): A controller that computes the global schedule and configures bridges.
• Centralized User Configuration (CUC): An interface for end-devices to request stream requirements.
• Allows a software-defined control plane to dynamically reconfigure the network for new production orders.

A seamless redundancy protocol that protects against packet loss due to cable breaks, electromagnetic interference, or faulty connectors. The sender transmits duplicate copies of a critical frame over disjoint paths.

• The receiver eliminates the duplicate based on a sequence number.
• Achieves zero switchover time, unlike traditional ring protocols.
• Critical for functional safety applications requiring a Packet Error Rate (PER) of 10^-9 or better.

A security and robustness gatekeeper that protects the network from faulty or malicious end-devices. It inspects frames at the ingress port before they enter the bridge.

• Uses a stream filter to match frames to a specific TSN stream based on MAC address and VLAN ID.
• A stream gate enforces a time-window, discarding frames that arrive outside their allotted slot.
• A flow meter polices the bandwidth, preventing a babbling idiot failure from flooding the network.