Q: How to implement secure remote access to IoT devices behind NAT for maintenance? Answer Options for remote IoT access: (1) MQTT reverse tunnel: persistent MQTT connection from device to cloud broker – cloud initiates via topic-based commands. (2) SSH…
Q: What industrial IoT protocols are most important and how do they compare? Answer Key industrial IoT protocols: (1) MQTT: lightweight pub/sub 2-byte header widely used for cloud integration. (2) OPC-UA: full-featured industrial interoperability protocol with information modeling built-in security.…
Q: How to design an IoT gateway architecture for edge computing and cloud synchronization? Answer Edge computing IoT gateway architecture layers: (1) Data acquisition layer: protocol drivers (Modbus OPC-UA BACnet) running as microservices. (2) Edge processing layer: time-series database (InfluxDB…
Q: What are the key considerations for IoT OTA firmware update design and implementation? Answer IoT OTA update design must address: (1) Atomic update: use A/B partitions so update failure never bricks the device. (2) Delta updates: send only the…
Q: How to integrate multiple sensor types into an IoT gateway using industrial protocols? Answer Industrial IoT gateways typically aggregate: (1) Modbus RTU (RS-485): poll registers from PLCs and sensors at configurable intervals. (2) Modbus TCP: for Ethernet-connected PLCs. (3)…
Q: What are the best practices for low-power IoT device design to achieve multi-year battery life? Answer Achieving multi-year battery life requires aggressive power management: (1) Choose the right sleep mode: Hibernate ( Stop (1-5 uA) > Sleep (100-200 uA).…
Q: How to implement end-to-end TLS security for IoT devices with certificate authentication? Answer For embedded TLS on IoT devices: (1) Use TLS 1.2 minimum – TLS 1.3 is preferred for lower latency. (2) Use mbedTLS or wolfSSL for embedded…
Q: What is the difference between MQTT MQTT-SN and CoAP protocols for IoT? Answer MQTT (MQ Telemetry Transport): TCP-based pub/sub protocol. Excellent for reliable always-connected devices. Overhead ~2 bytes header. Best for: gateways cloud-connected sensors. QoS 0 (at most once)…
Q: How to measure and optimize embedded Linux power consumption? Answer Power measurement: use a precision shunt resistor (1-10 mOhm) + oscilloscope with current probe or a bench power supply with current measurement. Software tools: powertop shows per-process power draw.…
Q: What are the security hardening steps for production embedded Linux devices? Answer Hardening steps: (1) Disable unused services (systemctl disable ). (2) Use AppArmor or SELinux to confine applications. (3) Remove SUID binaries where unnecessary. (4) Enable ASLR: CONFIG_ARCH_HAS_RANDOMIZE_BASE=y.…