+Client Simulation
+The lwm2m_client sample can run in simulation mode (native_sim) .
+Building the sample with native_sim will generate a binary that can be
+executed directly on the host machine. This allows to test all components
+locally.
+The native_sim simulation allows to connect the simulated Zephyr instance to
+the host network . Furthermore, simulated Zephyr endpoints have access to
+the internet via the host network, allowing testing of both a locally hosted
+instance of flownexus as well as a remote instance.
+To simulate endpoints easily, a script is provided that builds and runs the
+endpoints in a docker container. Setting up the network and running the
+simulation in a docker container ensures interoperability with different host
+systems.
+
+
Note
+
The native_sim simulation does not have a true random number generator and
+therefore the entropy source is limited. If a built simulation
+image is run multiple times, the CoAP message that registers the endpoint with
+the server may have the same message ID. The CoAP internal deduplicator will
+ignore this message if a previous message within NON_LIFETIME seconds
+(default 145 s) had the same message content and the same message ID. This
+can lead to the device not being properly registered with the server.
+
This issue only shows if the same client registers multiple times within 145
+s and only during simulation. Hardware with a true random number generator
+is not affected, in face the CoAP deduplication feature is necessary for
+reliable function. You can either wait for 145 s or rebuild the client. In
+case of a rebuild the entropy seed will be different and the resulting
+message ID will be different.
+
Prerequisites
+The simulation requires a working Docker installation.
+host:~$ apt install docker-ce
+
+
Simulating a single Endpoint
+The easiest way to run the simulation is to execute the simulate.py script
+without any arguments:
+host:~/workspace/flownexus/simulation$ python3 ./simulate.py
+No build/run options provided, build and run n clients with logging:
+ Warning: bindir will be cleaned, do you want to continue? [y/n]
+y
+
+Cleaning ./lwm2m_client/endpoint_binaries/, ./conf_tmp/
+Building Zephyr client [1/1]
+Building image from ./Dockerfile
+Starting container
+Starting zeth [1/1]
+Starting Zephyr client [1/1]
+
+*** Booting Zephyr OS build v3.7.0-rc3-75-gd06e95c49b75 ***
+[..]
+
+
You should now be able see one active endoint with the registration name
+urn:imei:100000000000000 the registered node in the Django Admin dashboard
+at https://flownexus.org/admin/.
+
+
+Simulation Script (simulate.py)
+
+
Options of the simulate.py script
+
host:~/workspace/flownexus/simulation$ python3 simulate.py --help
+usage: simulate.py [-h] [-n NUM_CLIENTS] [-v] [-b] [-r] [-d DELAY] [-l]
+
+Zephyr Build and Run Script
+
+options:
+ -h, --help show this help message and exit
+ -n NUM_CLIENTS Number of client instances to start. (1 - 254) (default: 1)
+ -v Enable logging (default: False)
+ -b Build the client (default: False)
+ -r Run the client. (default: False)
+ -d DELAY Client start delay [ms] (default: 0)
+ -l Connect to locally running Leshan server (default: False)
+
+
+
Simulating Multiple Endpoints
+The simulation allows to configure and start multiple Zephyr endpoints. The
+script takes care of assigning individual IP addresses and gateway settings to
+each endpoint. Furthermore it sets up the virtual network adapter (zeth) that
+connects the endpoints to the host network. For that reason, each endpoint has
+to be build before it can be started. The resulting binaries are stored in the
+lwm2m_client sample (e.g. lwm2m_client/endpoint_binaries/ep_0.exe). A set
+of devices can be build once and started by omitting the parameter -b.
+
+
Build and run 10 endpoints without logging
+
host:~/workspace/flownexus/simulation$ python3 simulate.py -b -r -n 10
+Cleaning ./lwm2m_client/endpoint_binaries/, ./conf_tmp/
+Building Zephyr client [10/10]
+Building image from ./Dockerfile
+Starting container
+Starting zeth [10/10]
+Starting Zephyr client [10/10]
+# Stop the simulation with <Ctrl+c>
+Stopping container
+
+
+
+
Warning
+
The simulate.py script supports max. 254 clients.
+
Connecting to a locally hosted Leshan server
+Connecting to a locally hosted Leshan server is possible by setting the -l
+flag. The script will connect the simulated Zephyr instances to the Leshan
+server running on the host machine. Internally, the script overwrites the
+LWM2M_APP_SERVER configuration option in the Zephyr lwm2m_client sample
+with the IP address of the container with the running Leshan server.
+If the Leshan server is started on the host natively (without docker compose),
+change the IP address in the Kconfig file (see next chapter) to
+coap://192.0.2.2:5683.
+
+
+Configuring the Firmware
+You can change the flownexus domain that you want to connect to by modifying
+the Kconfig file in the lwm2m_client sample.
+
+
Change LwM2M server to the public hosted eclipse leshan server
+
./simulation/lwm2m_client/Kconfig
+ config LWM2M_APP_SERVER
+ string "LwM2M server address"
+- default "coap://flownexus.org:5683" if !LWM2M_DTLS_SUPPORT
++ default "coap://leshan.eclipseprojects.io:5683" if !LWM2M_DTLS_SUPPORT
+
+
+
+- Leshan URLs:
-
+
+
+If you want to modify the firmware further, check Firmware Setup for
+more details on this topic.
+
+
Note
+
After making changes to Kconfig, make sure to delete the build directory
+to ensure that the changes are applied.
+
Attach to the running Container
+After starting the simulation, you can attach to the running container e.g. to
+attach to the Shell terminal of a running Zephyr instance:
+
+
Attach to the running container
+
host:~/workspace/flownexus/simulation$ python3 simulate.py -b -r -n 1
+Cleaning ./lwm2m_client/endpoint_binaries/, ./conf_tmp/
+Building Zephyr client [1/1]
+Building image from ./Dockerfile
+Starting container
+Starting zeth [1/1]
+Starting Zephyr client [1/1]
+Quit <q>; Attach to Container <a>
+a
+
+root@855c499d5a09:/home/workspace/flownexus/simulation# tio /dev/pts/0
+tio v2.7
+Press ctrl-t q to quit
+Connected
+(Press <Tab> to interact with the Zephyr Shell)
+
+ clear device devmem help history kernel lwm2m net
+ rem resize retval shell
+
+
+
By having access to individual nodes, you can interact with the Zephyr Shell
+and test different features. In particular, interacting with the LwM2M Shell
+can be useful to test the LwM2M client features.
+
+
+Manual build and run
+For development purposes, it can be useful to build and run the simulation
+manually. The following steps show how to setup zeth network, build and run the
+Zephyr lwm2m_client sample.
+
+
Manual build and run of the Zephyr lwm2m_client sample
+
host:~/workspace/flownexus$ west update # Update the Zephyr repository
+host:~/workspace/flownexus$ ../tools/net-tools/net-setup.sh start
+Using ../tools/net-tools/./zeth.conf configuration file.
+Creating zeth
+host:~/workspace/flownexus$ west build -b native_sim simulation/lwm2m_client -p -- -DCONF=overlay-lwm2m-1.1.conf
+host:~/workspace/flownexus$ west build -t run
+*** Booting Zephyr OS build v3.7.0-rc3-75-gd06e95c49b75 ***
+[..]
+<inf> net_config: IPv4 address: 192.0.2.1
+<inf> net_lwm2m_client_app: Run LWM2M client
+
+# Stop the simulation with <Ctrl+c>, do not forget to stop the zeth network
+host:~/workspace/flownexus$ ../tools/net-tools/net-setup.sh stop
+Using ../tools/net-tools/./zeth.conf configuration file.
+Removing zeth
+
+
+