To know about how to set payload in server side in COAP using contiki cooja simulator.
Step 1: Open a file at location:
home/user/contiki/examples/er-rest-examples/er-example-client.c
Payload set for client side
coap_set_payload(request, (uint8_t *)msg, sizeof(msg) – 1);
function set payload,
Step 2: contiki/apps/er-coap/er-coap-engine.c
Payload set for sever side
For example,
Char * res_msg = “Pressure”
coap_set_payload(response, res_msg, strlen(res_msg)); /* a const char str[] and sizeof(str) produces larger code size */
Step 3: Run the cooja simulator