IoT Systems Architecture and Design Questions

Covers architecture and design of distributed Internet of Things systems and connected embedded devices. Core topics include edge computing patterns, sensor and actuator network topologies, gateway and mesh network architectures, cloud integration and data pipelines, and trade offs between edge processing and cloud processing. Also includes networking protocols commonly used in constrained environments such as WiFi, Bluetooth, ZigBee, and LoRaWAN, plus connectivity strategies for unreliable networks including buffering, retries, offline operation, and data aggregation and filtering. Candidates may be evaluated on device to cloud data flow, scalability considerations from hundreds to millions of devices, performance and power trade offs on resource constrained hardware, deployment patterns for gateways and proxies, and high level fault tolerance and monitoring strategies.

HardSystem Design

64 practiced

Architect an OTA update system for 5 million IoT devices that supports staged rollouts, fast rollback, integrity verification, and fleet-level analytics for canary analysis. Describe package creation, use of CDN or regional caches, delta versus full images, cohort management, telemetry needed to detect regressions, and safety mechanisms to stop a harmful rollout.

HardTechnical

84 practiced

Design a memory-efficient algorithm and data structure for a gateway with limited RAM to deduplicate and order sensor events that may arrive out of order. Include expected memory bounds per device, eviction policy for old entries, how to checkpoint state to flash between reboots, and how to recover after a crash with minimal duplication to cloud consumers.

MediumSystem Design

68 practiced

Design a gateway service that ingests LoRaWAN uplinks and republishes messages to an MQTT broker while suppressing duplicates and preserving ordering where feasible. Specify metadata to attach, algorithms to detect duplicates in the presence of multiple gateways, how to make publishing idempotent, and trade-offs for state you must maintain for each device.

EasyTechnical

79 practiced

Describe the differences between star, tree, and mesh sensor network topologies commonly used in IoT deployments. For each topology list advantages and disadvantages with respect to scalability, reliability, latency, power consumption, and ease of maintenance. Provide scenarios where you would choose one topology over the others and explain why.

MediumSystem Design

71 practiced

Describe deployment patterns for IoT gateways across multiple geographic regions to optimize latency, data residency, and failover. Compare a centralized ingestion model versus regional edge ingestion, discuss synchronization of device metadata and device twin state, and propose a strategy for performing rolling gateway updates with minimal downtime.

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