We have two geographically separate data centers.  We are preparing to implement a new WAN connection (dark cloud) that would be used only for backup traffic.  The servers will have two NIC cards (production & backup) but what is the best way to ensure that the production and backup traffic doesn't mix?  At the moment we are just using static routes to get to the WAN, but looking to implement BGP between our SP and ourselves.  Internal RP is a mix of EIGRP and OSPF.  Cores are Cisco 6500s and WAN routers will soon be upgraded to ASRs.

Suggestions on solutions? Policy-based routing (PBR)? VRFs?

![Network Diagram][1]

  [1]: https://i.sstatic.net/Y8KFV.jpg