IoT Networking and Connectivity
What the exam tests
IoT Networking and Connectivity covers how a device reaches a platform: direct cellular access, gateway access, addressing, and the constrained-network protocols that make IP practical on small devices.
Core rules
- Direct access: a device with an integrated cellular module registers on the operator network and reaches the platform over the Internet or a private APN.
- Gateway access: short-range devices (ZigBee, BLE, RS-485) connect to a gateway that performs protocol conversion, local filtering and backhaul over Ethernet, Wi-Fi or cellular.
- Constrained networking: 6LoWPAN compresses IPv6 headers over IEEE 802.15.4; CoAP runs over UDP for request/response; MQTT runs over TCP for publish/subscribe; LwM2M provides device management over CoAP.
- Topologies: star for LPWA and many gateways; mesh for ZigBee and some industrial networks; tree for large metering deployments.
- Edge computing: local processing at the gateway reduces latency and backhaul cost.
Worked example
A factory has RS-485 Modbus energy meters. A gateway polls each meter with Modbus RTU, maps register values to named properties, then publishes JSON to the platform over MQTT/TLS. The platform never speaks Modbus. Modbus is a fieldbus for local serial segments; MQTT is the wide-area transport to the platform, so the gateway is the translation point.
Traps
Do not assume every device needs a public IP address: NAT and platform-initiated downlinks over an established session are normal. Do not say CoAP requires TCP; it is UDP-based. Do not treat a gateway as merely a repeater; it usually performs protocol conversion and local logic.