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| en:iot-open:communications_and_communicating_sut:high_level_communication [2019/05/27 09:42] – pczekalski | en:iot-open:communications_and_communicating_sut:high_level_communication [2020/07/20 09:00] (current) – external edit 127.0.0.1 | ||
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| + | ===== ===== | ||
| + | <box # | ||
| + | <box # | ||
| ===== Host Layer Protocols ===== | ===== Host Layer Protocols ===== | ||
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| The host layers protocols include session (SES), presentation (PRES) and application (APP) level, particularly APP (application) layer in the regular Internet communication is dominated by the HTTP protocol and XML-related derivatives, | The host layers protocols include session (SES), presentation (PRES) and application (APP) level, particularly APP (application) layer in the regular Internet communication is dominated by the HTTP protocol and XML-related derivatives, | ||
| Some IoT designed protocols are reviewed below. | Some IoT designed protocols are reviewed below. | ||
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| </ | </ | ||
| - | **MQTT Message**\\ | + | ===MQTT Message=== |
| MQTT is a text-based protocol and is data-agnostic. | MQTT is a text-based protocol and is data-agnostic. | ||
| A message is composed of a Topic (text) and a Payload (data). | A message is composed of a Topic (text) and a Payload (data). | ||
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| The payload (data) of the message is text as well, so in case one need to send binary data, it is necessary to encode it (e.g. Base64). | The payload (data) of the message is text as well, so in case one need to send binary data, it is necessary to encode it (e.g. Base64). | ||
| - | **MQTT Broker**\\ | + | ===MQTT Broker=== |
| MQTT Broker is a server for both publishers and subscribers. The connection is initiated from the client to the Broker, so assuming it is located outside of a firewall, it breaks firewall its boundaries. | MQTT Broker is a server for both publishers and subscribers. The connection is initiated from the client to the Broker, so assuming it is located outside of a firewall, it breaks firewall its boundaries. | ||
| The Broker provides QoS (Quality of Service), and it can retain message payload. There are three levels of MQTT Broker QoS (supplied in the message level). | The Broker provides QoS (Quality of Service), and it can retain message payload. There are three levels of MQTT Broker QoS (supplied in the message level). | ||
