@buckthorn Two CPEs do network extension point-to-point and have dropout problems, you need to go section by section to troubleshoot the possible causes. You can first test whether this end of the AP...

@SSpE SA Lifetime: Specify ISAKMP SA Lifetime in IKE negotiation. If the SA lifetime expired, the related ISAKMP SA will be deleted.

@yubik It is not very clear about your issue, what is your network layout? And what did you wanna achieve?

@DrBlingDaddy As I seen, it should be the IP address of each POE cam which is connecting to the switch ports now. It has said that on your pic: And to make sure the IP address does not change, better...

@cdnhk Do you mean ONE-ONE NAT? Take a look: How to configure One-to-One NAT

@J0S3PH It seems like still an issue on the DHCP Server, tried to set a static IP on the clients, can it work properly?