Frequently Asked Question on MQTT

What is Message Queue Telemetry Transport Protocol(MQTT)?

MQTT is a simple, lightweight messaging protocol used to establish communication between multiple devices. It is a TCP-based protocol relying on the publish-subscribe model. This communication protocol is suitable for transmitting data between resource-constrained devices having low bandwidth and low power requirements. Hence this messaging protocol is widely used for communication in the IoT Framework....

Working of MQTT

MQTT’s publish/subscribe (pub/sub) communication style, which aims to maximise available bandwidth, is an alternative to conventional client-server architecture that communicates directly with an endpoint. In contrast, the client who transmits the message (the publisher) and the client or clients who receive it (the subscribers) are not connected in the pub/sub paradigm. Third parties—the brokers—manage the relationships between the publishers and subscribers because they don’t communicate with one another directly....

Characterstics of MQTT

Lightweight: MQTT is designed to be lightweight, making it suitable for use in aid-restrained environments inclusive of embedded systems and low-strength devices. The protocol minimizes bandwidth and processing overhead, enabling green communication even on restricted networks. Publish-Subscribe Model: In the publish-subscribe version, clients (publishers) send messages to subjects, and different clients (subscribers) acquire messages from subjects of interest. This decoupling of producers and purchasers permits for flexible and dynamic conversation styles. Quality of Service (QoS) Levels: MQTT supports exclusive stages of message delivery warranty, referred to as Quality of Service (QoS). QoS levels range from 0 to 2, providing various stages of reliability and message transport guarantees, relying at the utility necessities. Retained Messages: MQTT lets in agents to store retained messages on topics, making sure that new subscribers acquire the maximum latest message posted on a subject right now after subscribing. This characteristic is beneficial for fame updates and configuration settings. Last Will and Testament (LWT): MQTT clients can specify a Last Will and Testament message to be posted by way of the broker in the occasion of an sudden consumer disconnect. This function affords a mechanism for detecting patron failures and dealing with them gracefully. Security: MQTT helps various protection mechanisms, consisting of Transport Layer Security (TLS) encryption and authentication mechanisms which include username/password and consumer certificates. These capabilities make certain the confidentiality, integrity, and authenticity of messages exchanged over MQTT connections....

Advantages of MQTT

This model is not restricted to one-to-one communication between clients. Although the publisher client sends a single message on specific topic, broker sends multiple messages to all different clients subscribed to that topic. Similarly, messages sent by multiple such publisher clients on multiple different topics will be sent to all multiple clients subscribed to those topics. Hence one-to-many, many-to-one, as well as many-to-many communication is possible using this model. Also, clients can publish data and at the same time receive data due to this two-way communication protocol. Hence MQTT is considered to be bi-directional protocol. The default unencrypted MQTT port used for data transmission is 1883. The encrypted port for secure transmission is 8883....

Disadvantages of MQTT

When compared to Constrained Application Protocol (CoAP), MQTT has slower send cycles. Resource discovery in MQTT is based on flexible topic subscription, while resource discovery in CoAP is based on a reliable system. MQTT lacks encryption. Rather, security encryption is accomplished by TLS/SSL (Transport Layer Security/Secure Sockets Layer). Building an internationally scalable MQTT network is challenging....

Frequently Asked Question on MQTT – FAQs

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