Hi,
A virtual server (VS) is a traffic-management object on the BIG-IP system that is represented by an IP address and a service. In your case, there is VS 10.8.6.19 with different services https, 10443, etc. VS directs the traffic according to your configuration to different pools or nodes (app servers). Your app servers is behind VS 10.8.6.19. How it works: the BIG-IP system typically translates the destination address of VS in a request to the actual address of a server node, and translates the actual source address in a response to the virtual server address.