Sorry for my poor english.
Well as those are provider modems, the physical layer stays allways up, but the IP layer or the connectivity itself is not reachable.
Is there anything simmilar to the SLA (service level agreement) that could check the conectivity either to a specific IP or service.
What about the 3G backup modem supported directly in OS, how does the controller know that it is the time to switch to the backup? Or how does the VRRP standby controller know, which WAN to choose from.
I know that the 650 is not designed as a boundary device, but as a typical branch controller, it might be able to sense WAN connectivity, i am now pretty amazed by the lack of such feature.
But as there are allways many useful undocumented features, i hope that somebody has a clue.
thanks