I ask to excuse my bad English.
I have a brief experience of successful application of RB 450.
Now we bought 2 pieces of RG-951.
On the first installed firmware v 5.26. I configured the router with NAT and IPSEC VPN.
At first sight everything works good.
But one model of IP Phone (Panasonic) works through VPN good, and other model not works.
I compared protocols of those phones and have not found any difference.
Then I take the second device, install in it firmware 6.11 and the same configuration.
Everything works, including both models of phones.
But now communication works with frequent interruptions, both Internet connection, and VPN.
What do I do incorrectly?