Connectivity Framework Annex F: Assessment Template: MQTT
F. 6.5 Implementation Viewpoint F. 6.5.4 Scalability Considerations
Data Objects( Section 4.2.4.1)
Apps( Section 4.2.4.2)
F. 6.5.5 Availability Considerations
Redundancy( Section 4.2.5.1)
Recovery( Section 4.2.5.2)
F. 6.5.6 Deployment Considerations
Platforms Constraints( Section 4.2.6.1)
Incremental Upgrades( Section 4.2.6.2)
Can the connectivity framework effectively handle an increasing number of data objects? What limits data object size?
MQTT does not provide a notion of data objects or data object caching; just the notion of a Topic. The number of topics supported by a MQTT-Server will depend on the server memory and the number of clients. The number of clients will be limited by the capabilities of the MQTT broker and the number of connections it can sustain.
There are no explicit message-size limits in MQTT, since it runs over TCP. MQTT-SN messages are over UDP will limit message size to what it can fit in a network datagram( 64KB).
Can the connectivity framework effectively support interface evolution for an increasing number of distributed application components?
Yes, MQTT can effectively support interface evolution for an increasing number of distributed application components, since the message are opaque. However, the applications will need to manage the message versioning and evolution.
Can the connectivity framework support continuous availability over a defined systemrelevant time period?
No, MQTT-Server does not support continuous availability over a defined system-relevant time period. The single point of failure introduced by the MQTT-Server will impact availability. Can the connectivity framework support recovery when fault conditions occur? No, MQTT does not support recovery when fault conditions occur.
Broker health should be monitored to ensure system availability. There should be mechanisms in place to re-start the broker in case of malfunction or failure.
Does the connectivity framework support the operating system( OS), the CPU and the resource constraints on the platform( s) being used?
MQTT is available for a number of platforms. Open-source implementations are available and could be built for target platforms. Does the connectivity framework facilitate incremental upgrades?
Yes, MQTT can facilitate incremental upgrades, since it is built on the publish-subscribe data exchange pattern.
During deployment, the main requirement is to configure all clients to connect to the same broker.
The centralization of the configuration on the broker simplifies deployment but it requires provisioning and maintenance of a service that is separate from all client applications that is common to all.
Integrating separate applications developed using different brokers requires consolidation of the brokers.
IIC: PUB: G5: V1.0: PB: 20170228- 118-