In one embodiment, a first request is received for a probe link from a client that has downloaded a page. The request is received from an application. A test may be performed to determine a server that could optimally service a content request from the client. After receiving the request, the content router sends a re-direct to the client where the re-direct causes the client to follow the re-direct to the server. The server then sends a re-direct back to the client, which the client follows by sending a second request to the content router. The second request is associated with the client and the round-trip time is calculated for the server. It is then determined if the location for the server should be designated as the content deliverer to the client based on the calculated round-trip time.