Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

VPN backing up Frame Relay

I am working on a design to use VPN to backup a frame relay network. I am using GRE tunnels to pass the traffic back and forth when the frame relay network is unavailable, using the "Backup Interface" command on the frame-relay sub interface.

This keeps the tunnel down until the frame network DLCI is down correctly. An idea came to mind though, is there a way to keep my tunnel interface down based on a lack of a route in the table? This would be similiar to the ISDN dialer-watch command, which looks for the presence (or lack of) a route, before bringing up the dialer. I'd like to apply the same theory to the VPN tunnel interface. This gives me a solution that prevents any potential telco related black holes, in the event that an interface stays up when it shouldn't.

Hall of Fame Super Silver

Re: VPN backing up Frame Relay


There might be something about your environment that I do not understand well which would impact this. But it seems to me that if there is no "interesting" traffic going through the GRE tunnel then the VPN will not become active. So if you configure floating static routes (instead of backup interface) as long as the Frame Relay is active its routes would be in the routing table and only if the Frame Relay fails would the floating static be put into the routing table which would trigger the VPN to come up. As long as the floating static route is not in the table then the VPN will not come up.

I am not clear why you care about keeping the VPN down. With normal dial backup we are motivated to keep the dial inactive because we pay based on the amount of activity. But with VPN we usually pay for the connection not for the amount of activity. Perhaps you can clarify why you want your design to work in this way.