I have two sites, both with 80/20 FTTC broadband connections that terminate at the standard white box BT modem. The connections both have fixed IP. I’d like to connect these up to each other and form a VPN between them so I can route traffic between the networks at either end. I am considering using Cisco 1921 routers with EHWIC-VA-DSL-A cards at either end to accomplish this. I am also planning at some point to add an E-band wireless connection between the sites that would present at either end as an RJ-45 connected to one of the GB interfaces on the 1921. I’d then like to use the E-band as the primary connection and route over the FTTC VPN as a backup. I am wondering if anyone has any hints and tips for me to give me some confidence in this solution - even if just to sanity check my plans.
The easiest way to accomplish your plan is to:
- Create a VPN connection over the FTTC connections.
- Create a second VPN connection over the E-band connections.
- Set up your internal routes through both VPN tunnels. Use a lower metric (=higher priority) on the desired VPN link.
That way, the lower metric causes the routes over E-band VPN to be used normally. If the link fails, the routes become inactive and the higher-metric routes via FTTC kick in.
If you use dynamic routes (e.g. with OSPF), make sure your VPN interface metrics are set according to the desired routing preferences.