...
The MQTT standard is defined for implementing a full publish/subscribe broker. However, the managed MQTT bridge run by ClearBlade IoT Core does not support all publish/subscribe operations, such as creating arbitrary topics that devices can use to send messages between them. Filtering can be accomplished with downstream processes running on Cloud Pub/Sub. ClearBlade IoT Core uses a predefined set of topics and specific topic formats.
Quality of
...
service (QoS)
The MQTT specification describes three Quality of Service ( QoS ) levels:
QoS 0, delivered at most once
QoS 1, delivered at least once
QoS 2, delivered exactly once
...