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2988 questions of the kind that actually get asked — in interviews, in architecture review boards, and by the person who has to run the thing at 3 AM. Every answer states the trade-off rather than the slogan, and says when the obvious choice is the wrong one.

All areas2988 Architecture Fundamentals91 Distributed Systems111 Data Architecture100 Cloud Architecture97 Networking96 API & Integration Architecture97 Reliability & Resilience99 Observability92 Performance & Capacity Engineering100 Security Architecture105 Cost Architecture & FinOps102 Business Architecture103 Architecture Communication102 Enterprise Architecture100 Legacy Modernization102 AI-Era Architecture106 Software Architecture & Engineering93 Architecture Patterns94 Architecture Decision-Making101 The Architect's Meta-Skills102 Delivery & Release Engineering103 Platform Engineering & Developer Experience102 Testing & Quality Architecture102 Data Platform Architecture98 Streaming & Real-Time Data103 Data Governance & Semantics91 Frontend & Experience Architecture101 Edge, Mobile & IoT98 Regulatory & Data Protection Architecture99 Assurance, Audit & Model Risk98
Difficulty Any beginner intermediate advanced

5 questions in Constrained Protocols.

  1. Constrained Protocols intermediate Multiple choice

    A battery-powered sensor on a cellular network holds an MQTT session. After quiet periods the server's messages stop arriving, though the device's socket is still open and sending works. Which change fixes it at the lowest energy cost?

    2 min answer mqttnatkeepalivebattery
  2. Constrained Protocols beginner Multiple choice

    A metered NB-IoT fleet must not record a reading twice, because readings drive a customer's bill. The team proposes QoS 2 so the broker delivers each publish exactly once. Which choice fits better?

    2 min answer mqttqosidempotencynb-iot
  3. Constrained Protocols intermediate

    A soil-moisture sensor runs on two AA cells, about 2,000 mAh usable. It wakes every 15 minutes, sends roughly 60 bytes, and sleeps. Sleep draw is about 10 uA. Each transmission cycle takes roughly 2 seconds at an average 30 mA while the radio is active. Estimate the battery life, and say which assumption you would attack first.

    3 min answer batteryduty-cycleenergyiot
  4. Constrained Protocols advanced

    An MQTT 5 broker cluster serving 120,000 sensors starts alerting on disk at 03:00 every night, and the oldest of those alerts is three weeks old. Publish rate is flat at roughly 900 messages per second, connected clients sit at 118,000, and the broker reports 340,000 sessions and rising. No messages are being dropped yet. What failed, and which design decision made it possible?

    3 min answer mqttsessionsbrokerqueueing
  5. Constrained Protocols intermediate

    Devices are battery-powered with intermittent low-bandwidth connectivity. What protocol properties matter, and what is usually chosen wrongly?

    1 min answer protocolsmqttcoappower