Looking for guidance on GTM Active/Active and fail over for regions

Am new to F5 GTM and am looking for some guidance or pointers to any relevant doc's. We currently have F5 GTM's in Europe and US. As part of a new project we are implementing a new remote access solution which will consist of 2 appliances in Europe (DC-A,DC-B) 2 in US(DC-A,DC-B) and 1 in Asia.

The setup we are looking to achieve is the following.

Active/Active US. If both vpn appliances are down GTM will direct users to Europe Active/Active Europe. If both VPN appliances are down GTM will direct users to US Active for Asia if the VPN appliance is unavailable users will be redirected to Europe

Below is my planned setup for base config on the GTM's:

1. Create the server objects on both GTM's and specify the Public IP of each of the external interfaces The server objects will be: europe_vpn_a: Public iP europe_vpn_b: Public iP us_vpn_a: Public iP us_vpn_b: Public iP asia_vpn: Public iP

    

2. Create a Virtual Server for each device. Again public IP's for https europe_vpn_a_vs Public iP Service Port HTTPS europe_vpn_b_vs Public iP Service Port HTTPS us_vpn_a_vs Public iP Service Port HTTPS us_vpn_b_vs Public iP Service Port HTTPS asia_vpn: Public iP Service Port HTTPS

    

3. Create Pools and add servers to pools. The Pools and pool members will be US-Global-Pool-Ras (us_vpn_a,us_vpn_b) Europe-Global-Pool-Ras (europe_vpn_a,europe_vpn_b) ASIA-Global-Pool-Ras (asia_vpn)

    

4. Define a wide IP to respond to DNS for both pools

    

Can you point me in the right direction regarding ensuring active, active for the regions, and fail over ?