In order to achieve this we need to get Dynamic DNS(DDNS) registered name for both sites from ISP. So once we haveDDNS configured for both sites, then every minute it will change the tunnel destination to what ever IP address, DDNSname will be usedfor the remote site.
Instead of crypto map we would use crypto Profile using VTI so that tunnels get automatically re establish. The beauty of Profile is that you can run Routing Protocols through it and you don't have to constantly change the crypto maps, every time you change network topology.
So we will make use of event manager to implement DDNS----