it's the same thing you deal with in Linux, it's standard TCP/IP routing.   You can't route private subnets directly over the internet.  You have to create a "WAN".   Not try to directly route over the internet.   Your WAN will create a private network and tunnel through the Internet.   OpenVPN would be one possible solution.  A very generalized scenario could be:  Once you have the WAN set up, the internet side of these routers would be a real internet address (e.g. 62.x.x.x.x) so the two WAN devices can reach each other.   They create a VPN tunnel with a new subnet, say 10.3.0.x.       The primary side WAN router would have a leg on the 10.1.0.x subnet, say with IP address 10.1.0.10   Your default route on the EQL SAN side would be 10.1.0.10.   On the DR side that router would have a leg on the 10.2.0.x subnet, say 10.2.0.10.  The default GW on the DR side would be 10.2.0.10.   The router knows how to move packets between the networks using standard routing.  Sounds like all you are missing is the "WAN"  VPN  tunnel between the sites.  You want something that will encrypt the traffic between sites anyways.   Does that help?   Regards, 
Hi,  we currently have a rack of EqualLogic SAN and NAS infrastructure (2 x PS6510E, FS7500), a stack of two PC8024F 10Gb switches, 2 m1000e blade chassis enclosures, with the A1 fabric being a stack of m6220 1Gb switches (A2 fabric a stack of the same thing), the B1 fabric being a stack of m8024k 10Gb switches, (B2 fabric a stack of the same thing), and a stack of two PC6224 1Gb switches (top of rack gig-e).  We have all this connected with the 10Gb SAN network being its own private 10.1.0.x network and vlan, nice and isolated from everything else.  The blades can access iSCSI shares via their 10Gb nics which are all on this 10.1.0.x network.  The 1Gb nics on the blades are on a public network, and the FS7500 client ports are on this network too via the 6224's, so NFS connections are made via the 1Gb public network. We plan to invest in an additional PS series array to host at a backup site, for replication.  At the same time, we plan to purchase a FS7610 for our primary site to take advantage of our 10Gb infrastructure, and move the existing FS7500 to our backup site so we can replicate iSCSI volumes and NAS containers. This is where we could use some help, because now several things will have changed.  Now the SAN must be on the public network for replication to succeed, AND in order to take advantage of 10Gb connectivity and mount NFS shares from the FS7610 via 10Gbit, we need to leverage the 10Gbit nics and switches for the NAS client network, which are already being used for iSCSI traffic (and will be used in the future for vmware hypervisor connections to the SAN).  In the FS7610 install and setup guide, it says We can move the SAN and it's network to a dedicated subnet and VLAN that is on the public network without issue, but my main concern is being able to satisfy the networking recommendations/requirements for the FS7610, and to avoid local SAN/NAS traffic from going through a router, to ensure 10Gb connections.  Any tips or advice is much appreciated! 
Help with FS7610, PS Series SAN, 10Gb Network design