by Paolo Patierno

The Internet of Things ... Babel

LinuxDay Napoli 2016

Senior Software Engineer at Red HatMessaging & IoT team

@ppatierno

Perché sono cosi forti:

● Proprietary vs Open protocols

● Standard protocol comparison– Architecture– Implementation & Weight– Data transport & Manipulation– IoT communication patterns– Security

AgendaAgenda

Perché sono cosi forti:

● Difficult to port applications– Requires re-coding all applications

● Difficult to integrate– Application level bridge for translating formats

● Restricted platform support– Limited to whatever vendor provides

Proprietary protocolsProprietary protocols

Perché sono cosi forti:

● Simple application porting– Re-coding is no needed

● Simple integration– Well known messages format

● Broader platform support– Everyone can implement for a platform

Open (standard) protocolsOpen (standard) protocols

Perché sono cosi forti:IoT “languages” on Babel towerIoT “languages” on Babel tower

HTTP

CoAP

STOMPDDS

XMPP

MQTTAMQP

Perché sono cosi forti:StandardizationStandardization

● HTTP– IETF standard (RFC 2616 is HTTP/1.1)

● CoAP– IETF standard (RFC 7252)

● MQTT– 3.1.1 version OASIS and ISO/IEC 20922

● AMQP– 1.0 version OASIS and ISO/IEC 19464

Perché sono cosi forti:Architecture : HTTP & CoAPArchitecture : HTTP & CoAP

● Client/Server– Request/response

● HTTP : synchronous● CoAP : (also) asynchronous

● HTTP is ASCII based

● CoAP is binary basedClient Server

Perché sono cosi forti:Architecture : MQTTArchitecture : MQTT

● Broker centric– Broker receives subscriptions from clients on topics– Broker receives messages and forward them– Clients subscribe/publish on topics– No flow control

Publisher

BrokerPublisher

Subscriber

Subscriber

Topic

Topic

Subscriber

Perché sono cosi forti:Architecture : AMQP 1.0Architecture : AMQP 1.0

● “Peer to peer” nature– Generic concepts of containers and nodes

● Containers : clients and brokers● Nodes : queues, topics/subscriptions or just ... endpoints

– Multiplexing on connection– Flow control

client

producer (consumer)

broker

queue

Perché sono cosi forti:Implementation & WeightImplementation & Weight

● HTTP– Client more complex (ASCII parser)– More bytes to pay on data transfer– Connection oriented via TCP

● CoAP– HTTP-like but binary– Connection less via UDP– Client more simple than HTTP

Perché sono cosi forti:Implementation & WeightImplementation & Weight

● MQTT– Client simple to develop (spec about 70 pages)– Constrained devices (smallest packet 2 bytes)– Connection oriented via TCP

● AMQP– Client more complex– Full featured – Connection oriented via TCP + multiplexing

Perché sono cosi forti:Data transport & ManipulationData transport & Manipulation

● HTTP & CoAP– Content-Type based on MIME

● MQTT– Payload agnostic

● No data types● No metadata● Any data format (text, binary, JSON, XML, ...)

– Peers must agree on serialization/deserialization

Perché sono cosi forti:Data transport & ManipulationData transport & Manipulation

● AMQP– Message

● Header : system and custom/user properties● Body : opaque

– Metadata– Data Type System– Peers can use Content-Type and Content-Encoding– Filter on properties

Perché sono cosi forti:IoT Communication PatternsIoT Communication Patterns

Telemetry

Information flows from device to other systems for conveying status changes in the device

Inquiries

Requests from devices looking to gather required information or asking to initiate activities

Commands

Commands from other systems to a device or a group of devices to perform specific activities

Notifications

Information flows from other systems to a device or a group for conveying status changes in the world

1:N 1:N

Perché sono cosi forti:IoT Communication PatternsIoT Communication Patterns

● Publish/Subscribe– Telemetry– Notification

● Request/Reply– Command– Inquiry

Perché sono cosi forti:IoT patterns : resourcesIoT patterns : resources

● HTTP & CoAP– REST architecture for CRUD operations on

resources– URIs + POST, GET, PUT & DELETE method

● CoAP : a device act as “server”

Perché sono cosi forti:IoT patterns : resourcesIoT patterns : resources

● MQTT– Topic based– Publish/Subscribe “for free”– Request/Response needs additional effort (on topic

semantic)building1

room1

floor1 floor2

room1room2

temp humidity temp humidity

Perché sono cosi forti:IoT patterns : resourcesIoT patterns : resources

● AMQP– Address based– Publish/Subscribe & Request/Response “for free”

– Brokered (with “store and forward”)● Queues : for point to point and request/response● Topics/Subscriptions : for publish/subscribe

– Routed● Routing messages between peers● No “store and forward”

Perché sono cosi forti:SecuritySecurity

● SSL/TLS– For authentication and encryption

● Payload encryption

● HTTP : basic & digest authentication

● CoAP : Datagram TLS (DTLS)

● AMQP : SASL for authentication

● MQTT : username/password on connection

Perché sono cosi forti:SecuritySecurity

Perché sono cosi forti:ConclusionsConclusions

● Devices– How much they are constrained ?

● Network– How much it is reliable ?

● Message rate– How many messages per second ? QoS ?

● Processing data– Do the system need more info on processing ?

Perché sono cosi forti:ConclusionsConclusions

Perché sono cosi forti:ResourcesResources

● MQTT– Eclipse Paho (clients) : https://www.eclipse.org/paho/

– Eclipse Mosquitto (servers) : https://mosquitto.org/

– Apache ActiveMQ Artemis (brokers) : https://activemq.apache.org/artemis/

● AMQP– Apache Qpid (clients/brokers) : https://qpid.apache.org/

– Apache ActiveMQ Artemis (brokers) : https://activemq.apache.org/artemis/

● CoAP– Eclipse Californium : https://eclipse.org/californium/