This circuit emulation configuration could be used in a DR situation. rtr1 is at the HQ site, rtr2 is at the remote site. rtr3 is at the disaster/failover site for HQ. It utilizes EEM with object tracking as an event source, so it requires IOS 12.4(2)T or above.
Given a fault-tolerant, routable IP connection, this provides a fault tolerant analog circuit, especially useful in legacy telephony and utility applications. Click "read more" for configuration details.