IoT

What is the “Internet of Things”?

A network of everyday physical objects—like sensors, appliances, vehicles—equipped with connectivity and small computers so they can collect data, communicate over the Internet, and be monitored or controlled remotely.

What is the Web of Things (WoT)?

A set of standards and best practices (defined by the W3C) that sit on top of IoT, using Web technologies (HTTP, JSON-LD, Thing Descriptions) so any device can be discovered and interacted with in a uniform, plug-and-play way.

What is MQTT and why is it good for IoT?

MQTT is a lightweight publish/subscribe messaging protocol. Devices (publishers) send to a broker under topics, and others (subscribers) listen. It keeps connections open, uses minimal bandwidth, and supports delivery guarantees via QoS levels.

How does CoAP differ from HTTP in IoT?

CoAP is “HTTP for constrained devices”—it runs over UDP, provides REST-style methods (GET/POST), has lower overhead, and supports multicast. HTTP uses TCP and opens a new connection per request, making it heavier for tiny devices.

What role does TLS play in IoT communication?

TLS encrypts traffic (HTTPS or MQTT over TLS), ensuring data confidentiality and integrity. It uses certificates (public/private keys) to establish a secure channel before any application data is sent.

What happens at QoS 0 (“At most once”)?

The message is sent exactly once without acknowledgment. It’s fastest but may be lost if the network drops it.

What happens at QoS 1 (“At least once”)

The sender retries until it receives an ACK. This guarantees delivery but can result in duplicate messages.

What happens at QoS 2 (“Exactly once”)?

QoS 2 uses a four-step handshake so each message arrives only once, with no duplicates. It’s the most reliable but adds extra latency and overhead.

What is a Constrained Device App (CDA)?

Constrained Device App (CDA)? is an applikation fokused on resource-limited hardware that reads sensors, makes simple decisions, and publishes results upstream with minimal power and memory use.

What is a Gateway Device App (GDA) do?

A GDA serves as an intermediary that connects IoT devises to the Cloud or other networks, managing data trafiic and providing protocol translation

How do Edge Tier and Cloud Tier differ?

• Edge Tier: CDA + GDA layer for real-time, local processing and offline resilience.

• Cloud Tier: Heavy storage, large-scale analytics, machine-learning training, and user dashboards.

What is a digital twin?

A live digital replica of a physical device or system, updated with real-time data so you can simulate, analyze, and test “what-if” scenarios without touching the actual equipment.