Connectivity Framework Annex F : Assessment Template : MQTT
F . 6.5 Implementation Viewpoint F . 6.5.1 System Architecture Considerations
Peer-to-Peer vs . Broker :
( Section 4.2.1.1 )
Data-Centric vs . Device / App-Centric : ( Section 4.2.1.2 )
Explicit vs . Implicit Governance : ( Section 4.2.1.3 )
F . 6.5.2 Data Considerations
Content-Based Selection ( Section 4.2.2.1 )
Time-Based Selection ( Section 4.2.2.2 )
Does the connectivity framework require running a special process or broker ? Broker-based .
F . 6.5.3 Performance Considerations
Real-Time ( Section 4.2.3.1 )
Latency and Jitter vs . Throughput ( Section 4.2.3.2 )
It requires running MQTT-Server , a special broker process , for clients to communicate .
Does the application code ( or business logic ) have to be aware of the other endpoints in order to participate in information exchange ?
The application code ( or business logic ) does not have to be aware of the other endpoints to participate in data exchange . MQTT is only a connectivity transport . Data-centric or device-centric connectivity frameworks can be built with application-specific code . Is the governance explicit and shareable ?
No , the governance is not explicit and shareable . Governance is enforced by the server implementation . The means for this are not standardized .
Can a content-filter specify the data subset of interest ?
No , the data subset of interest cannot be specified by content . The content is opaque to MQTT . Can sub-sampling specify the data subset of interest ?
No , one cannot subscribe to a sub-sampled data subset of interest . MQTT attempts to deliver the published messages to all the subscribers on a topic .
Does the connectivity technology support real-time data distribution ? Is the latency deterministic ( smaller jitter is better )?
No , MQTT is a TCP and broker-based protocol , and is not intended for real-time .
Binary protocol offers low overhead , but the use of TCP and relay via a broker provides non-deterministic latency . How does the latency and jitter change with throughput ? What limits the throughput ?
Implementation dependent , but use of a broker is likely to make latency highly dependent on throughput .
Small protocol overhead benefits throughput , but the use of broker limits this to what a single broker can relay .
IIC : PUB : G5 : V1.0 : PB : 20170228 - 117 -