I 've 2 sites coneccted with a Frame relay link. On each site I 've c2610 routers running ip eigrp routing protocol.
On the HQ site I also have an ASA5500 that acts as endpoint of ipsec vpn to other branchs including the one I'm talking.
In these branch site I 've install a adsl router (not CISCO) that create a ipsec vpn link with the ASA as a backup of the FR link. The way I do it is with a static route in the branch office with a distance of 200.
I'm looking for a solution where I can share traffic between the fr link and the vpn. It seems that the aswer to my question is to create a GRE tunnel between the 2 routers and into the ipsec VPN in order to carry ip routing traffic by second path. Is this coorect? What are the ip addressing considerations if my branch ip address LAN is 10.110.32.0 /24 my HQ is 10.10.0.0/16 and de FR link is 10.210.32.0/30. Can you suggest me an addressing solution without configurating a loopback interface.