Hi Kaleb,

We want to use CoAP over DTLS for device to cloud IoT communications without having to renegotiate sessions and to also be able to issue async cloud commands.  The heart beat would keep the session alive through the NAT traversal of most firewalls.

This could be handled at the CoAP layer with additional timers and pings but it would be more efficient and cleaner to do at the DTLS layer.

The bytes sent from the heart beats can add up particularly over cellular or other per byte cost models.  It seems it could be done with fewer traffic bytes at the network layer.

Thanks for the fast response,
Craig