How does an NMEA 2000 network support redundancy for critical navigation data?

• A. By encrypting all PGNs on the bus.
• B. By turning off all non-essential devices to save power.
• C. By allowing multiple sensors of the same type to publish data, cross-checking data from multiple sources, and using gateways/routers to distribute data to multiple displays.
• D. By using a single master device that controls all data.

Answer: (C)

In NMEA 2000, redundancy for critical navigation data comes from having multiple sources publish the same type of data, using cross-checking among those sources, and routing that data to several displays through gateways or routers. When more than one sensor provides the same PGN, the system can compare the values to catch discrepancies and rely on the strongest or most consistent source. Gateways or routers then distribute the data to multiple displays or network segments, so if one device or path fails, other paths continue delivering the essential information to all displays that need it. This multi-source, cross-checking approach—plus flexible data distribution—avoids dependence on a single device and makes critical data available even in failure scenarios. Note that encryption or simply shutting off devices wouldn’t inherently improve reliability, and a single master concept goes against the multi-master design of NMEA 2000.