Questions about F5 BIG-IP Multi-Datacenter Configuration

We have an infrastructure with two datacenters (DC1 and DC2), each equipped with an F5 BIG-IP using the LTM module for DNS traffic load balancing to resolvers, and the Routing module to inject BGP routes to the Internet Gateways (IGW) for redundancy. Here’s our current setup (based on the attached diagram):

Each DC has a BIG-IP connected to resolvers via virtual interfaces (VPI1 and VPI2).

Routing tables indicate VPI1->DC1 and VPI2->DC2.

Each DC has its own IGW for Internet connectivity.

Question 1: Handling BIG-IP Failures

If the BIG-IP in one datacenter (e.g., DC1) fails, will the DNS traffic destined for its resolvers be automatically redirected to DC2 via BGP? How can BGP be configured to ensure this?

Is it feasible and recommended to create a HA Group including the BIG-IPs from both datacenters for automatic failover? What are the limitations or best practices for such a setup across remote sites?

Question 2: IGW Redundancy

Currently, each datacenter has its own IGW. We’d like to implement redundancy between the IGWs of the two DCs.

Can a protocol like HSRP or VRRP be used to share a virtual IP address between the IGWs of the two datacenters? If so, how can the geographical distance be managed?

If not, what are the alternatives to ensure effective IGW redundancy in a multi-datacenter environment?

Question 3: BGP Optimization and Latency

We use BGP to redirect traffic to the available datacenter in case of resolver failures.

How can BGP be configured to minimize latency during this redirection? Are there specific techniques or configurations recommended by F5 to optimize this?

Question 4: Alternatives to the DNS Module for Redundancy

We are considering a solution like the DNS module (GSLB) to intelligently manage DNS traffic redirection between datacenters in case of failures. However, this could increase costs.

Are there alternatives to the DNS module that would achieve this goal (intelligent redirection and inter-datacenter redundancy) while leveraging the existing LTM and Routing modules? For example, advanced BGP configurations or other built-in features of these modules?

Thank you in advance for your advice and feedback!