1608 Remote handset cuts off after 5 minutes. Connected via vpn

[glenn335]

I have a 1608 handset connected via a vpn to an IP Office v2 on 8.1 software. When on an inbound or outbound call you get cut off after 5 minutes.
The router is a draytek 2710. I have checked its not the tunnel rebuild time. Any suggestions welcome.
Thanks

 

[tlpeter]

The voice traffic does not know where to go after 5 minutes and stops.
This is really a network issue.
Make a wireshark trace to see what actually happens.

BAZINGA!

I'm not insane, my mother had me tested!