Connectivity Framework Annex F : Assessment Template : MQTT
F . 6.4 Functional Viewpoint F . 6.4.1 Core Framework Layer Functions
Data Resource Model
( Section 4.1.1 )
ID & Addressing ( Section 4.1.2 )
Data Type System ( Section 4.1.3 )
Data Resource Lifecycle ( CRUD ) ( Section 4.1.4 )
State Management ( Section 4.1.5 )
Publish-Subscribe ( Section 4.1.6 )
Request-Reply ( Section 4.1.7 )
Discovery ( Section 4.1.8 )
Exception Handling ( Section 4.1.9 )
Data Quality of Service ( QoS ) ( Section 4.1.10 )
Does it provide a data resource model ? Summarize the salient aspects . No , MQTT does not provide a data resource model . Messages are directed to Topics , which represent logical flows or streams .
There is no explicit data resource model in MQTT . A single Topic might be used to represent data from multiple resources and the association will be encoded in the data and maintained by the clients .
Does it provide a way to identifying and addressing data objects ? Summarize the identification and addressing scheme .
No , it does not provide a way of identifying and addressing data objects . Addressing of individual resources within the streams is left to the application code . Does it provide a data type system ? Summarize the salient aspects .
No , MQTT does not define a data type system . It transmits opaque data to be interpreted by the applications .
Does it provide a means of managing a data object ’ s lifecycle ? Summarize the salient aspects .
No , it does not provide a means of managing a data object ’ s lifecycle . There is no explicit resource management . This would be implemented by the client applications .
Does it provide a means to manage the recent history of data objects ? Summarize the salient aspects .
No , it does it not provide a means to manage the recent history of data objects . Given that there is no resource management there is also no state management provided by MQTT .
However , the MQTT broker can retain messages to be delivered to late joining applications and clients could use this to build state management at the application level .
Does it provide a means to publish and subscribe the state of data objects ? Summarize the salient aspects .
It provides a means to publish and subscribe messages on topics , but since there is no dataresource model , applications have to maintain the mapping of messages to state updates on data objects .
Does it provide a means to request the state of data objects ? Summarize the salient aspects .
No , it does not provide a means to request the state of data objects . Does it provide a means to discover the data objects ? Summarize the salient aspects .
No , it does not provide a means to discover the data objects . Discovery is implicit by the fact that applications communicate via a broker . All client applications must connect to the same broker that has full knowledge of the topology of the system .
Does it provide a means to handle exceptions when quality of service or connectivity violations happen ? Summarize the salient aspects .
No , it does not provide a means to handle exceptions when quality of service or connectivity violations happen .
Does it support data QoS ? Summarize the scope and coverage . Highlight the salient aspects .
MQTT provides limited QoS support . It includes best efforts and reliable delivery , and a minimal level of durability so that subscribers can receive a special message after a publisher goes offline .
IIC : PUB : G5 : V1.0 : PB : 20170228 - 115 -