CSI Message Queuing & Event-Driven Architecture 3

Question 1

Which messaging protocol is commonly used for lightweight, low-bandwidth IoT device integration and operates on a publish/subscribe model over TCP?

Accepted Answer

MQTT

Answer

MQTT (Message Queuing Telemetry Transport) was designed for constrained devices and low-bandwidth networks, using a pub/sub model with a small packet overhead ideal for IoT integration.

Question 2

In event-driven architecture, what is an 'event schema registry' primarily used for?

Accepted Answer

Storing and enforcing versioned schemas to ensure producers and consumers agree on event structure

Answer

A schema registry (such as Confluent Schema Registry) stores Avro/JSON/Protobuf schemas and validates messages against them, preventing schema incompatibilities from breaking consumers.

Question 3

What is 'back-pressure' in a message-driven integration pipeline?

Accepted Answer

A flow-control mechanism where a slow consumer signals the producer to slow down or pause to avoid being overwhelmed

Answer

Back-pressure is a signaling mechanism that allows a downstream component to inform upstream producers to reduce throughput, preventing memory exhaustion and cascading failures.

Question 4

When designing a message-based integration, what does 'message TTL' (Time-To-Live) control?

Accepted Answer

How long a message remains in the queue before being discarded or moved to a dead letter queue if not consumed

Answer

TTL sets an expiry duration on messages so that stale, time-sensitive events (e.g., real-time stock prices) are automatically removed if not consumed within the acceptable time window.

Question 5

Which pattern is best suited for integrating a legacy system that cannot be modified to publish events directly into a modern event-driven architecture?

Accepted Answer

Change Data Capture (CDC) from the legacy system's database transaction log

Answer

CDC reads the database transaction log (e.g., via Debezium) to detect changes without modifying the legacy application, converting database changes into events for the modern platform.

(CSI) Certified System Integrator Practice Test

(CSI) Certified System Integrator Practice Test

CSI Message Queuing & Event-Driven Architecture 3