Message sequence charts
The below message sequence chart shows the initialization of the LwM2M carrier library:
![msc {
hscale = "1.1";
Application,"LwM2M carrier Library";
Application=>"LwM2M carrier Library" [label="lwm2m_carrier_init()"];
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_BSDLIB_INIT"];
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_CONNECTING"];
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_CONNECTED"];
Application<-"LwM2M carrier Library" [label="Success"];
Application=>"LwM2M carrier Library" [label="lwm2m_carrier_run()"];
|||;
"LwM2M carrier Library" :> "LwM2M carrier Library" [label="(no return)"];
...;
}](../../../_images/mscgen-a1790a84d88406112d292b32f2c215cf5212778d.png)
The following message sequence chart shows the bootstrap process:
![msc {
hscale = "1.1";
Application,"LwM2M carrier Library";
|||;
--- [label="Device is not bootstrapped yet"];
|||;
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_DISCONNECTING"];
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_DISCONNECTED"];
"LwM2M carrier Library" rbox "LwM2M carrier Library" [label="Write keys to modem"];
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_CONNECTING"];
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_CONNECTED"];
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_BOOTSTRAPPED"];
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_LTE_READY"];
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_REGISTERED"];
}](../../../_images/mscgen-1c34960f76dfb471138e2f53b50f4d136756b395.png)
The following message sequence chart shows FOTA updates:
![msc {
hscale = "1.1";
Application,"LwM2M carrier Library";
|||;
--- [label="Carrier initiates modem update"];
|||;
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_FOTA_START"];
...;
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_DISCONNECTING"];
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_DISCONNECTED"];
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_CONNECTING"];
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_CONNECTED"];
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_LTE_READY"];
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_REGISTERED"];
...;
}](../../../_images/mscgen-eae29a3a4d5272e92aa606994b90e7b235f90dae.png)
The following message sequence chart shows a successful CA certificate initialization:
![msc {
hscale = "1.1";
Modem,Application,"LwM2M carrier Library";
|||;
--- [label="LwM2M carrier library is initializing"];
|||;
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_CERTS_INIT"];
...;
Application rbox Application [label="Write CA certificates to modem security tags"];
Modem<<=Application [label="modem_key_mgmt_write(...)"];
...;
Modem->Application [label="Success"];
Application rbox Application [label="Provide LwM2M carrier library the security tags for CA certificates"];
Application rbox Application [label="LwM2M carrier event data set to ca_cert_tags_t"];
Application->"LwM2M carrier Library" [label="Success"];
...;
}](../../../_images/mscgen-38995290e6ae17ef77c6ebc8c8c363dbe653a400.png)
The following message sequence chart shows that the CA certificate initialization fails if the application fails to provision the keys to the modem:
![msc {
hscale = "1.1";
Modem,Application,"LwM2M carrier Library";
|||;
--- [label="LwM2M carrier library is initializing"];
|||;
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_CERTS_INIT"];
...;
Application rbox Application [label="Write CA certificates to modem security tags"];
Modem<<=Application [label="modem_key_mgmt_write(...)"];
...;
Modem->Application [label="Failure"];
Application->"LwM2M carrier Library" [label="Failure"];
"LwM2M carrier Library" rbox "LwM2M carrier Library" [label="LwM2M carrier library fails to initialize"];
Application<-"LwM2M carrier Library" [label="Failure"];
...;
}](../../../_images/mscgen-5b7673c80efa39fbccd6134292000f8f6c45441a.png)
The following message sequence chart shows that FOTA fails at run time if an invalid CA certificate is provided during the initialization:
![msc {
hscale = "1.1";
Application,"LwM2M carrier Library";
|||;
--- [label="Carrier initiates modem update"];
|||;
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_EVENT_FOTA_START"];
...;
"LwM2M carrier Library" rbox "LwM2M carrier Library" [label="Apply security tag that contains invalid certificate"];
|||;
Application<<="LwM2M carrier Library" [label="LWM2M_CARRIER_ERROR_FOTA_CONN (NRF_ECONNREFUSED)"];
...;
}](../../../_images/mscgen-20c401f678fec96e7a2816dcd125a469e0e9001c.png)