Some Questions About MQTT

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Anonymous
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Hello All,

I have three questions about MQTT protocol and its usage in WICED.

1.As I understood, there's no timeout mechanism in MQTT protocol.

However in Wiced API MQTT snips, WICED_MQTT_TIMEOUT is defined and in AWS demos MQTT_REQUEST_TIMEOUT is defined.

Is this timeout something you added such that after some time it'll return error? Or Is it a part of the MQTT protocol which I missed?

2.The ACK mechanism of MQTT is different for different QoS choices. Doesn't MQTT run over TCP, do we really have to run an ACK mechanism? What improvement does this mechanism add on top of TCP?

3.As I understood with AWS, we can only use QoS 0 or 1 (the AWS demo also uses QoS 1), what would you propose to get QoS 2 functionality while using AWS?

4.Is there a sample application which implements MQTT over TLS?

Thanks.

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1 Solution
Anonymous
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For #1, please check sample source code.

WICED_MQTT_TIMEOUT and MQTT_REQUEST_TIMEOUT are used for semaphore.

They look added to detect some error on application layer.

For #4, have you tried sample application named secure_mqtt?

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2 Replies
Anonymous
Not applicable

For #1, please check sample source code.

WICED_MQTT_TIMEOUT and MQTT_REQUEST_TIMEOUT are used for semaphore.

They look added to detect some error on application layer.

For #4, have you tried sample application named secure_mqtt?

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Anonymous
Not applicable

Thanks for your answer.

Yes, actually I've now figured out that secure_mqtt actually connects over TLS with certificates.

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