I have two 881 routers, which I have to install into two different locations and connect each one of these 881 routers to existing networks with and existing routers (one per location). Two new computes in each office will be connected to these new 881 routers. After that I will have to set up VPN in order for those two locations to communicate with each other. I tried different way to configure the routers. I was never able to connect the new router 881 to existing router with the WAN port on 881. I can connect the LAN on 881 to the existing router and see other computers on the existing network, but I think I need to connect through WAN in order to configure VPN. Please help.