Technical guide to CAN gateway design, CAN FD routing, UDS diagnostics, domain isolation and automotive Ethernet integration.
A vehicle gateway is responsible for more than forwarding frames. It defines which domain can talk to another domain, which diagnostic services are allowed, how messages are transformed and how network faults are contained. In centralized and zonal architectures, the gateway becomes the boundary between legacy CAN networks and Ethernet-oriented compute.
CAN FD increases payload size and data phase speed, but it does not remove the need for deterministic scheduling and careful bus loading. Gateways help normalize legacy CAN signals into service-oriented data streams that can be consumed by middleware, telematics, OTA agents and cloud analytics.
Every frame that reaches the gateway is checked against an identifier whitelist before it is allowed to cross into another domain. Rate limiting caps how fast a given ID may repeat, and anomaly indicators flag frames that break expected timing or payload patterns — a common signature of a compromised ECU. Only after this pipeline does the gateway resolve the routing table and, for diagnostics, mediate between UDS sessions on CAN and their DoIP equivalent on Ethernet.