Techniques for modifying the performance of a transport layer protocol in response to a request for content are disclosed. A connection can be established between a content distribution server and an end user computer according to preconfigured parameters. When a request for content is received over the connection, the content distribution server can determine one or more parameters relating to the performance of the connection using information from the request. The content distribution server can modify the connection at the transport layer according to the one or more parameters. Thereafter, the transport layer can manage delivery of the requested content to the end user computer in accordance with the modified parameters. In various embodiments, the content distribution server includes a modified TCP protocol stack which adjusts timing, pacing, and buffer allocation associated with a connection in response to requests from an application-layer data source.