DUAL WAN WITH YEALINK

[jolouis]

Have you guys checked the registration timers on the phones? From the phone's point of view, it has no clue that the internet connection has failed/changed (how would it, it's behind NAT so unless it was trying to determine the public IP of the network it would never know... and it has no reason to ever want to do that). So the phone carries on as usual as if nothing has changed. The problem is the registrations on the PBX side are still pointing at the old public IP (the internet connection that failed).

In order for the PBX to see the phones on the new IP, the phones need to re-register. A reboot of course does this manually. The phones also have registration timers that determine how often the re-registration happens on it's own. I can't remember the defaults now but it's typically 3600 or something like that (once per hour). If you turn that time down (say 120 seconds... once every 2 minutes) then you should find things working better. At worst there will be 2 minutes of downtime when the internet flips over.

The only other option would be to rig up some scripting/process on the router to notify the phones when the internet connection changes. I would expect that's far beyond what you will be able to achieve though, especially on the low end Cisco units.