Mqtt; Topics - ZyXEL Communications NR/FWA Outdoor Series User Manual

28.1.1 MQTT

The Zyxel Device supports MQ Telemetry Transport (MQTT) to send messages for always-on, direct
communications between an agent (A, the Zyxel Device, ZD), controller (C), the MQTT broker (MQTT)
and other clients. The MQTT broker (MQTT) routes and delivers messages between the controller and
agent. Messages can be encrypted with TLS (Transport Layer Security) for end-to-end message security
and integrity.
Figure 160 MQTT Broker

28.1.2 Topics

An agent exposes a service element to a controller by publishing a topic. Controllers use topic filters to
subscribe to specific published topics that they can manage.
A topic uses a hierarchical structure with forward slash "/" characters for organizing topics and to identify
the exact location of a service element. For example, "myhome/livingroom/temperature", "myhome/
bedroom/temperature", "myoffice/meetingroom/temperature".
Note: Response Topic in the Agent screen is a topic filter where you can subscribe to multiple
topics at once using wildcards.
Topic in the Controller screen is a topic name used to publish a topic. It must not
contain wildcards.
28.1.2.1 Topic Filter Wildcards
Wildcard characters can be used in topic filters, but not in topic names. [MQTT-4.7.1-1].
The number sign ('#' U+0023) is a wildcard character that matches any number of levels within a topic.
The multi-level wildcard represents the parent and any number of child levels. The multi-level wildcard
character must be specified either on its own or following a topic level separator. In either case it must
be the last character specified in the topic filter [MQTT-4.7.1-2]
For example, if a client subscribes to "sport/tennis/player1/#", it would receive messages published
using these topic names:
• "sport/tennis/player1"
• "sport/tennis/player1/ranking"
• "sport/tennis/player1/score/wimbledon"
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