WSO2 Message Broker (WSO2 MB) uses two transport protocols for the purpose of brokering messages between publishers and subscribers. These protocols are the Advanced Message Queueing Protocol (AMQP) and the Message Queueing and Telemetry Transport (MQTT).
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| Parameter Name | Description | Default Value |
|---|---|---|
| maximumRedeliveryAttempts | The maximum number of times WSO2 MB should attempt to redeliver a message that has not reached a subscriber. For example, when this value is set to 10, another 10 attempts will be made to deliver the message. The default value can be changed depending on your reliability requirements. Read more about message redelivery. | 10 |
| allowSharedTopicSubscriptions | If this parameter is true, a durable subscription to a topic can be shared among multiple subscribers. That is, multiple clients can subscribe to a topic in WSO2 MB using the same client ID. Read more about durable subscriptions to topics. | false |
| allowStrictNameValidation | If this parameter is true, the queue names and topic names will be validated according to the AMQP specification. When this parameter is set to false, it is possible to use ":" in topic names. Read more about this in 'Adding topics from management console'. | true |
Refer the description of the broker.xml file for further details.
Message Queueing and Telemetry Transport
The Message Queueing and Telemetry Transport (MQTT) is a lightweight, broker-based publish/subscribe messaging protocol, which enables an extremely lightweight publish/subscribe messaging model. WSO2 MB 3.0.0 and later versions fully support MQTT version 3.1.0, and partially supports version 3.1.1.
The MQTT protocol allows a message to be sent to a topic based on three levels of QoS (Quality of Service) as explained below.
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