Semtech UDP Packet Generator

SUPG (Semtech UDP Packet Generator) is a lightweight version of ChirpStack Simulator used to simulate LoRaWAN® gateways and devices. Similar to ChirpStack Simulator, SUPG allows ChirpStack users to test their setups and to observe how ChirpStack really works in action.

Building

How to build

As for many C++ projects, SUPG can be built using the CMake build system. The minimum required version of CMake is 3.12. To build SUPG, use the following commands:

$ bash scripts/pre-build.sh
$ bash scripts/build.sh

The binary file will be located at bin/supg.

Note

Running the bash script scripts/pre-build.sh before building is required because cryptopp is not fully supporting CMake as of now.

Configuration

How to generate a new configuration file

A sample TOML configuration file will be automatically generated along the binary file at bin/supg.toml. You can also generate your own configuration file using the --generate-config-file command-line option:

./bin/supg --generate-config-file [OUTPUT_FILE]

where OUTPUT_FILE is the path to the output file.

For example: ./bin/supg --generate-config-file ./bin/my_supg.toml

How to configure

Name	Type	Meaning	Requirements
general.log_level	int	Log level (trace = 6, debug = 5, info = 4, warn = 3, error = 2, critical = 1, off = 0).	>= 0, <= 6
network_server.host	string	IP of ChirpStack Gateway Bridge's UDP listener.	Not empty
network_server.port	int	Port of ChirpStack Gateway Bridge's UDP listener.	> 0
simulator.duration	int	The time running the simulation (s).	> 0
simulator.device.first_eui	string	EUI of the first configured device.	Length = 16
simulator.device.first_address	string	Address of the first configured device.	Length = 8
simulator.device.first_network_session_key	string	Network session key of the first configured device.	Length = 32
simulator.device.first_application_session_key	string	Application session key of the first configured device.	Length = 32
simulator.device.count	int	Number of devices.	> 0, <= 1000
simulator.device.uplink_interval	int	The time between two consecutive uplink transmissions (s).	> 0, < simulator.duration
simulator.device.f_port	int	FPort.	> 0
simulator.device.payload	string	Uplink payload.	Not empty
simulator.device.frequency	int	Frequency (Hz).	> 0
simulator.device.bandwidth	int	Bandwidth (Hz).	> 0
simulator.device.spreading_factor	int	Spreading-factor.	> 0
simulator.device.f_cnt	int	Uplink frame counter.	>= 0
simulator.gateway.first_id	string	ID of the first configured gateway.	Length = 16
simulator.gateway.min_count	int	Minimum number of receiving gateways.	> 0
simulator.gateway.max_count	int	Maximum number of receiving gateways.	>= simulator.gateway.min_count

Example

[general]
log_level = 4

[network_server]
host = "localhost"
port = 1700

[simulator]
duration = 60

[simulator.device]
first_eui = "0000000000000000"
first_address = "00000000"
first_network_session_key = "00000000000000000000000000000000"
first_application_session_key = "00000000000000000000000000000000"
count = 1
uplink_interval = 10
f_port = 10
payload = "test_packet_1234"
frequency = 868100000
bandwidth = 125
spreading_factor = 12
f_cnt = 0

[simulator.gateway]
first_id = "0000000000000000"
min_count = 1
max_count = 1

Note

• Unlike ChirpStack Simulator, SUPG does not use ChirpStack Client to set up gateways and devices before or tear them down after the simulation (to avoid installing gRPC). Therefore, everything relating to the simulation must be manually handled. A fixed set of gateways and devices will be a lot easier to manage than a random one.
• The k-th gateway of the configured gateway set will have:
  • Gateway ID: simulator.gateway.first_id + k
• The k-th device of the configured device set will have:
  • Device EUI: simulator.device.first_eui + k
  • Device address:** simulator.device.first_address + k
  • Network session key: simulator.device.first_network_session_key + k
  • Application session key: simulator.device.first_application_session_key + k
• As running the simulator multiple times on a fixed set of devices might result in ChirpStack refusing to process uplink frames due to conflicted frame counters, the simulator.device.f_cnt configuration parameter should be modified (usually increased) each time you run the simulator to avoid recreating old devices.

Running

How to set up ChirpStack before running

As mentioned above, because SUPG does not set up ChirpStack while running, you have to create/update everything beforehand.

• To set up gateways, all the configured gateways must be created.
• To set up devices, a service-profile, a device-profile, an application and all the configured devices must be created. You also need to activate these devices using their associated device address, network session key and application session key.

How to run

To start SUPG, use the following command:

./bin/supg --config [CONFIG_FILE]

where CONFIG_FILE is the path to the configuration file.

For example: ./bin/supg --config ./bin/my_supg.toml

What happens during the simulation

After the simulation starts, devices will periodically send uplink frames (and handle downlink frames, if any) to the configured network server through the gateways assigned to them.

The simulation will be gracefully stopped after a simulator.duration interval.

How to stop

SUPG will be terminated by any of the following conditions:

• After a simulator.duration interval.
• When an exception is thrown.
• When receiving a SIGINT signal.

When the simulation stops, all the gateways and devices (as well as the service-profile, the device-profile and the application) created earlier should be deleted.

Note

• When creating a new device-profile, set:
  • LoRaWAN MAC version: 1.0.3
  • LoRaWAN Regional Parameters revision: B
  • ADR algorithm: Default ADR algorithm
  • Uplink interval: 60
• To send downlink payloads to a simulated device, you can enqueue device queue items to its queue using ChirpStack Application Server web-interface. The data need to be encoded to Base64 format. This could be done by running SUPG with the --base64-encode command-line option.

License

This project is licensed under the terms of the MIT license.