WE have a BGP configuration that advertises the Main site Internet router subnet to the PE router. If the Main site looses Internet connectivity, the BGP configuration will advertise the Main site Internet subnet to the DR PE router.

This allows the DNS to stay the same during Failover situations.

We have a CSS at the Main site that has VIP addresses in the 2.1.1.64 subnet and web requests are sent to it, then if the corresponding service is up, it gets sent to the Main site server, if that server is down, they get sent to DR through the Main site, then through the MPLS network.

I want to do the same thing in reverse at the DR site, to (if just Main site internet is down) route to the Main site 2.1.1.64 subnet which will be a CSS VIP, sitting in the DR site switch between the DR router and DR PIX.

If that server is down to redirect web requests to the DR server.

This way DNS never gets changed.

CAn I have the Dr CSS interface in the DR subnet of 6.2.1.128

and have the VIP address in the Main site subnet of 2.1.1.64?

Would it be benificial to have the CSS devices communicate via an app service?