We had another VPN link go out last week between 2 sites on our Gen1 system. Instead of just going into the remote management feature of one of the routers, I decided to drive out to one of the affected sites to confirm some things on site that I suspected:
The internet at the site was fully functional. I was able to access the internet with my laptop plugged into the modem and into the site router. The same site router has 11 other VPN links to our other sites and those were fully functional. I confirmed function by looking down the LAN's at other sites and ping the routers & repeaters and enter management of the routers at other sites. I could not see or ping any device through the affected link, However, The "status" window of the router indicated that all VPN links including the bad link were in "connected' status. It is important to note that I am testing the link at this point with my laptop, not with the radio equipment, and I can't pass data between the 2 affected routers on the bad tunnel. We do not have any network alarms on our system but an alarm on the internet connection would not have triggered because the internet did not "fail." Also an alarm triggered by VPN "disconnect" would also not have triggered because the router indicates that the "bad" tunnel was in "connect" mode.
Again - all I did was click on the "tunnel test" button of the bad tunnel in the site router and that refreshed or re-established the one bad link out of 12 and the 2 sites became fully functional again without re-booting the site or any device. In the past I have left a link between 2 unimportant sites in default and they do heal thy self after a day or so, just as unexpectedly as the quit.
Since this last episode I did some surfing on the net and discovered that it is not unusual for Vz 4G VPN's to indicate connection but stop passing data in other M2M applications. It may also happen with other services but my research was with Vz. There doesn't appear to be a known cause but speculation suggests: unstable connections between devices, unstable devices, More than one router and LANS with conflicting IPs behind the primary modem/router, signal strength/interference, or faulty or unstable IP service or devices in Vz network between here & there. There is also suspicion that Vz or some device may put the path in "sleep mode" due to inactivity and it takes something other than normal data to re-establish/wake-up the link.
I do not have a cure for the problem but "experts" on the net suggest changing the NAT or other settings and wait to see if it doesn't happen again. ???? I'm not much of an IT tech and not comfortable with blind trial & error fooling around until I happen on a fix (if one exists) or more likely really screw things up.
I believe that Radio4866, Curt34, myself and others are dealing with the same issue of loss of ability to pass data thru a VPN tunnel. It is far more critical on GEN2 than it is with GEN1. You are showing the symptoms of loss of data exchange with the controller and in the case of GEN2, radios can't register on the affected site because the controller can't validate the radios. If you have ever disabled active ID's or tried to place mobiles on the air before you activate ID's, the mobiles will do nothing except display "out of range." I believe we are having an Internet/VPN reliability issue or perhaps issues with the router or modem.