New Trends in IoT and COAP

Lecture 5: New Trends in IoT

• Discusses new trends in IoT

COAP

• Constrained Application Protocol (COAP) is designed for devices and networks with limited resources.
• COAP is optimized for low power consumption, limited processing capabilities, low memory/storage, and low bandwidth networks.
• COAP is a web transfer protocol for constrained nodes and networks.
• COAP is designed for Machine to Machine (M2M) applications, such as smart energy and building automation.
• COAP is based on a Request-Response model between end-points.
• Client-Server interaction is asynchronous over a datagram oriented transport protocol like UDP.
• COAP uses a simple request-response model optimized for IoT.
• COAP runs on UDP, making it faster and more efficient in constrained environments, unlike HTTP which uses TCP.
• COAP supports asynchronous communication, alleviating the need for persistent connections and reducing resource consumption.
• COAP is ideal for smart devices like thermostats, sensors, and automation systems.
• COAP utilizes GET, POST, PUT, DELETE, a model similar to HTTP but in a more optimized manner.
• Clients send requests to the server using methods like GET, POST, PUT, or DELETE.
• Servers process the request and send a response.
• Since COAP is asynchronous, it doesn't keep a connection open like HTTP/TCP.
• Messages are exchanged as "datagrams" over UDP, which makes communication fast and lightweight.
• COAP is built over UDP instead of TCP, and has a light mechanism for reliability.
• COAP architecture is divided into two main sub-layers: Messaging and Request/Response.
• The messaging sub-layer is responsible for reliability and duplication of messages.
• The request/response sub-layer is responsible for communication.
• COAP features confirmable, non-confirmable, piggyback, and separate messaging modes.
• Confirmable and non-confirmable modes represent reliable and unreliable transmissions, respectively.
• Piggyback is used for client/server direct communication where the server sends its response directly after receiving the message.
• Separate mode is used when the server response comes in a message separate from the acknowledgment, and may take some time to be sent by the server.

XMPP

• Extensible Messaging and Presence Protocol (XMPP) communication protocol for message-oriented middleware.
• XMPP is based on XML.
• XMPP enables the real-time exchange of structured data.
• XMPP is an open standard.
• XMPP uses a client-server architecture.
• XMPP is decentralized, so no central server is required.
• XMPP discovery of services resides locally or across a network, plus the availability information of these services (busy-online) are provided.
• XMPP is well-suited for cloud computing.
• XMPP supports machine-to-machine or peer-to-peer communications across a diverse set of networks.
• XMPP offers decentralization, meaning no central server is needed, enabling anyone to run their own XMPP server.
• XMPP has open standards, so there are no royalties or permissions needed to implement these specifications.
• XMPP ensures security through authentication and encryption.
• XMPP has flexibility
• XMPP doesn't support QoS (loss data _latency)
• Text-based communications induce higher network overheads compared to Binary-based systems.
• Binary data must first be encoded to base64 before transmission, increasing the data size by 33%.
• XMPP can be used for video, file transfer, gaming and IoT applications.
• In IoT, XMPP is suitable for smart grids and social networking services.

AMQP

• Advanced Message Queuing Protocol (AMQP) is an open standard for passing business messages between applications or organizations.
• AMQP is a binary application layer protocol.
• A frame is a basic unit of data.
• AMQP features security, reliability, interoperability, routing, queuing, and is based on an open standard.
• AMQP provides at-most-once, at-least-once, and exactly-once messaging guarantees.
• 'At-most-once' means each message is delivered once or never.
• 'At-least-once' means each message is certain to be delivered, but may be delivered multiple times.
• 'Exactly-once' means the message will always certainly arrive and do so only once.
• There's the Open frame type, which is for connection management and opens a connection between client and broker.
• The Begin frame type, which is for managing sessions and starts a new session within an open connection.
• The Attach frame type creates a link (sender or receiver) between the client and broker for managing sessions.
• The Transfer frame type is for message transfer and transfers actual messages from the sender to the receiver.
• The Flow frame type is for controlling the flow and controls the flow rate of messages between sender and receiver.
• The Disposition frame type informs the sender about message status (e.g., received, accepted, rejected) and is for message state management.
• The Detach type ends a link but keeps the session active; it's also for session management.
• The End frame type closes the session (but not the connection) and is for session management.
• The Close frame type fully closes the AMQP connection between the client and broker and is for connection management.
• AMQP components are Exchange, Queue and Bindings.
• Exchange is part of the Broker that receives messages and routes them to Queues.
• Queue is for separate queues for separate business processes, where consumers receive messages from queues.
• Bindings are the rules for distributing messages, saying who can access what message and the destination of the message
• Direct, Fan-out and Topic are AMQP Exchanges
• Targeted QoS (selectively offering QoS to links), Persistence (message delivery guarantees), Delivery of messages to multiple consumers, Possibility of ensuring multiple consumption, Possibility of preventing multiple consumption, and High speed protocol are all AMQP Features.
• AMQP is used for monitoring and global update sharing.
• AMQP can be used to connect different systems and processes so they can interact.
• AMQP can allow servers to respond to immediate requests quickly
• AMQP can delegate time consuming tasks for later processing.
• AMQP can distribute a message to multiple recipients for consumption.
• AMQP enables offline clients to fetch data at a later time.
• AMQP can introduce fully asynchronous functionality for systems.
• AMQP increases reliability and uptime of application deployments.