Which route advertisement configuration must be done on the Tier-1 Gateway to advertise the load balancer virtual IP to the Tier-0 Gateway?

To successfully advertise the load balancer's virtual IP (VIP) from the Tier-1 Gateway to the Tier-0 Gateway in VMware NSX-T, configuring the Tier-1 Gateway to "Advertise All LB VIP Routes" is essential. This specific configuration allows the Tier-1 Gateway to inform the Tier-0 Gateway about the IP addresses used by the load balancer services, ensuring that traffic destined for the virtual services can be properly routed.

By selecting the option to advertise all load balancer VIP routes, the NSX-T infrastructure is set up to propagate the necessary route information, which is vital for seamless communication and connectivity between different network segments. This configuration enables upstream routers (like the Tier-0 Gateway) to recognize and direct traffic intended for the VIPs effectively.

In contrast, other options such as advertising SNAT IP routes or all static routes either do not pertain to the specific requirement of sharing VIP information or would not provide the necessary advertisement context for dynamic routing and load balancing scenarios. The functioning of these services relies heavily on the visibility and routing of VIPs, making it crucial to use the correct settings on the Tier-1 Gateway.