we have multiple locations installed IP cctv surveillance setup all are connected in internet with static IP. we have a centralized monitoring location to monitor all other locations, now we are using software installed in a computer to monitor individual locations. now we are planing to setup a VPN network for all the locations to connect all our NVR's in our centralized location for better connectivity and speed. kindly suggest which model routers will be the best solution for VPN server and VPN client locations.