Hardware-enforced scheduling gates and seamless frame replication for sub-microsecond deterministic packet transport in mission-critical ADAS networks.
Without frame preemption, a low-priority 1500-byte diagnostic packet starting transmission right before a scheduled gate opens would delay the critical frame by up to 12.3 microseconds on 1Gbps links. To prevent this, switches historically enforced empty guard bands. IEEE 802.1Qbu splits transmitting best-effort frames into fragments, allowing the critical frame to cut through instantly.
For steer-by-wire and automated driving steering actuators, network failure is catastrophic. IEEE 802.1CB duplicates critical Ethernet frames at the source and sends them across disjoint physical cable paths. The receiving end-station forwards the first arrival to application memory and discards the second duplicate packet in hardware.