The load balancer plug-in routes all incoming HTTP or HTTPS requests to instances. However, if HTTPS routing is enabled, an HTTPS request will be forwarded by the load balancer plug-in to a server using an HTTPS port only. HTTPS routing is performed on both new and sticky requests.
If an HTTPS request is received and no session is in progress, then the load balancer plug-in selects an available instance with a configured HTTPS port, and forwards the request to that instance.
In an ongoing HTTP session, if a new HTTPS request for the same session is received, then the session and sticky information saved during the HTTP session is used to route the HTTPS request. The new HTTPS request is routed to the same server where the last HTTP request was served, but on the HTTPS port.