...
Gateway settings | |||
---|---|---|---|
Adapter Target | Select a different adapter, please see respective documentation for more information. | ||
Adapter Setting (MQTTServerSettings) | |||
XmlFilePath | File path to the policy file.
| ||
ServerName | Is used as the an indicator in the xml XML policy file. | ||
IP Address | The address of the MQTT broker. This can be a be in IPv4 address or a hostname like localhost | ||
Port | The port on which the MQTT broker is running, | ||
use TLS | Should be turned on when the broker is using TLS authentication. (off by default)
| ||
UserName | Is passed to the server for authentication if the field is not empty (not used by default). | ||
PassWord | Is passed to the server for authentication when the UserName field is not empty (not used by default) | ||
QoS | (Quality Of Server) is an agreement between the broker and client that defines the guarantee of delivering a message: 0 : At most once => There is acknowledgement between broker and client other than regular TCP , fast, unreliable (packet loss)) 1 : At least once => The sender buffers the value until a ‘PUBACK’ is returned by the broker. Message can be send sent multiple times (, slower, reliable) 2 : Exactly once => The sender sends the message, the broker returns a ‘PUBREC’. Sender The sender is returning a ‘PUBREL’ and the server again returns a ‘PUBCOMP’ command to finalize the send sending process. (slow, very reliable)
| ||
Lifecycle settings |
|
...
QoS | known as | speed | reliability | remarks |
---|---|---|---|---|
0 | fire & forget | fast | poor | Messages can get lost in unstable connections. Very suitable for wires local connection |
1 | single handshake | slower | good | No message is lost. Can lead to duplicate messages. but is much faster than QoS 2 |
2 | double handshake | slowest | exact | If it is getting the message exactly once is more important than performance. Quite an overhead compared to the other 2 levels |
...
MQTT can work with an online broker, but is more commonly used with a local broker. There are lots a lot of brokers available. An overview can be found at: https://en.wikipedia.org/wiki/Comparison_of_MQTT_implementations
...
For testing purposes we recommend to use using a client like i.e. MQTT.fx https://mqttfx.jensd.de/
...