aws_iot sample: the purpose of delayed connect_work

[Johan Kopra]

I have been trying the aws_iot sample in nRF Connect SDK v2.7.0 for build target nrf7002dk/nrf5340/cpuapp, in which connect_work is scheduled with a 5 second delay in the function on_net_event_l4_connected. What is the purpose of this delay?

As a test I have tried replacing the 5 second delay with K_NO_WAIT, and noticed that aws_iot_connect returns error -116 with an increased rate (although this error also occasionally happens with the K_SECONDS(5) delay), is this the reason for the 5 second delay? Is it recommended to always have some amount delay between a NET_EVENT_L4_CONNECTED event and calling aws_iot_connect?

[Håkon Alseth]

Hi,

 

Johan Kopra said:

At first I tried concatenating NET_EVENT_IPV4_DHCP_BOUND to the L4_EVENT_MASK and adding a corresponding log message to l4_event_handler, but did not see evidence of NET_EVENT_IPV4_DHCP_BOUND events. Eventually I was able to see NET_EVENT_IPV4_DHCP_BOUND events by using a separate callback for them.

My apologies, I should have given an example here, but I'm glad to hear that you found a solution to this.

Johan Kopra said:

With a little testing I have observed up to a 10 second delay between the l4-connected event and NET_EVENT_IPV4_DHCP_BOUND event. AWS connection seems to work when attempted after NET_EVENT_IPV4_DHCP_BOUND without adding a delay.

Glad to hear that the initial connection is more stable now. This is an interesting find. I tested a couple of networks, and got both of these events almost simultaneously (milliseconds apart). I'll report your findings back to the team responsible for these samples.

 

Kind regards,

Håkon