LYuan and everyone in this thread, I appreciate your efforts in trying to trouble shoot this issue. I don't have much to add to the conversation but would like to offer a summation of what I know from this issue.
My info: Hitron CGN3 - Bridged Mode, FW 4.1.4.4 or 4.2.4.1, 20x3 channels bound on 35/3Mbps tier and speedboosts upto 96Mbps. All signal levels are good but Rogers indicates high level of packet loss 14%??. Truck is here on Monday. RG6 and Cat6 everywhere no spitters and cable is direct from the demarc to modem. Both IP4 and IP6 connections with Rogers using 6To4. Everything works really well...when it works.
In bridged mode the modem will appear to not respond around the 36-48h mark and do so very consistantly. This even happens when no one is home and useage is very low. There are CGN3s in the field that are reporting over 100d of uptime on 4.2.4.1 in gateway mode. When the modem does fail, some exisiting connections may continue to operate for a short time afterwards but only continuting doing what they are doing. I cannot get to CGN3 modem IP address any longer and all WAN traffic is stopped. My router (ASUS RT-AC66) reports WAN ethernet port to the CGN3 is up but no traffic.
I concur with the finding that it's looking like a Ethernet resource issue on the CGN3. It was an interesting finding that LYuan made about the ping times to the various interfaces. Mine are 0.3ms to the LAN interface on AC66, 0.32ms to WAN and 23.2ms to the CGN3 7.x.x.x IP. Oddly pings to www.google.ca were 16.7ms at this same time!!
Unless you are getting a Cisco, gateway swaps have not helped anyone yet with this issue....and I bought mine so I am looking for a solution.