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Overview of Developing a JET Application Using IDL


To develop JET applications in languages other than Python, you need the interface definition language (IDL) APIs and a Message Queue Telemetry Transport (MQTT) library.

An IDL is a programming-language agnostic way of defining APIs.

The MQTT protocol is used to notify clients about Junos OS events. MQTT is a publish-subscribe based messaging protocol for use on top of the TCP/IP protocol. The publish-subscribe messaging pattern requires a message broker. The message broker is responsible for distributing messages to the interested clients based on the topic of a message. Clients register with the message broker and inform the message broker about the topics for which they are interested in receiving messages. For more details, see

Figure 1: Developing a JET Application Using IDL
Developing a JET
Application Using IDL

Table 1: Steps Involved in Developing a JET Application Using IDL

Workflow Step

Link to Workflow Step

A and B

Downloading and Compiling the IDL File


Creating an Unsigned Package by Using the Python Packaging Tool


Deploying an Application Package on a Device Running Junos OS