I have several energy meters (with a web server embedded) distributed in many buildings, all these sensors are connected to the local network so that can be accesed through a browser to see the real time data.
I am trying to access to each of theses devices from my office, but none of these devices has a public IP.
I am evaluating these solutions:
1) Use a VPN router like Cisco rvs4000, create a VPN account (IPsec) into the router and allow traffic to those port from my office.
2) Create a VPN with a persistent connection between each device (using a router I dont know which one) and a VPN server which will be located on my office. This will allow me to create a web site (branding) which will handle web request and send them to each device.
3) Create a VLAN: I am looking a cost effective solutions for this. Do you know a router or topology for this porpuse?
What do you think could be the best (technical and economical) solutions?