The present invention leverages an existing content delivery network infrastructure to provide a system that enhances performance for any application that uses the Internet Protocol (IP) as its underlying transport mechanism. An overlay network comprises a set of edge nodes, intermediate nodes, and gateway nodes. This network provides optimized routing of IP packets. Internet application users can use the overlay to obtain improved performance during normal network conditions, to obtain or maintain good performance where normal default BGP routing would otherwise force the user over congested or poorly performing paths, or to enable the user to maintain communications to a target server application even during network outages.