Part Number: CC3235MODSF
Other Parts Discussed in Thread: CC3235MODASF
Hi,
On our devices equipped with the CC3235MODASF, they sporadically need a long time to get an IP address.
To explain a little our application, we are using hibernate, and wake up typically every couple of hour to exchange a few https packets. We have devices at a few hundreds customers, where the dhcp sometimes fails.
The dhcp process typically takes 1-2secs which is ok, but can go up to our current dhcp timeout of 12sec. Then we hibernate for an incremental backoff duration (2sec, 60sec, 120sec, 240sec and so on)
When it fails, I sometimes get the the event: SL_NETAPP_EVENT_DHCP_IPV4_ACQUIRE_TIMEOUT
I am quite sure that some of this delay comes from the DHCP server infrastructure (as well as the backoff of 2sec which is probably on the aggressive side), however I also see some strange behavior from the CC3235.
To understand better, I am sniffing through ssh on the AP to which the device is connected and have a few questions about what I see.
Here is a successful example showing only the dhcp packets:
Here is another successful example showing all packets.
And here is a dhcp request which ended in failure:
My questions are:
- The nwp always send a couple of packet at the same time, is it normal?
- The nwp resends packets every ~1sec. Is it normal?
- During the failed exchange, the nwp sent 4 DHCP discover, then switched to DHCP request before receiving a DHCP offer. Is it normal?
- in swru455 it explain the different dhcp modes, currently I use the default which is indicated to be "Full Renew Process". Shall the nwp reuse the old address between hibernate cycle?
All that said I would gladly take any advice regarding DHCP.
Thanks!
Cédric
