The forwarding delay and throughput of a proxy server play significant role in the overall network performance. It is widely known that the forwarding delay of proxy¡¦s application layer is much larger than that of lower layers. This is because for a general purpose operating system, the receiving or sending data in application layer needs to move data through the TCP/IP stack and also cross the user/kernel protection boundaries. TCP Splice can forward data directly in TCP layer without going up to the application layer. This can be achieved by modifying the packet headers of one TCP connection from the original server to the proxy so that the TCP connection can be seamlessly connected to another TCP connection from the proxy to the client. To maintain the caching ability of proxy, TCP Tap can duplicate packets before they are forwarded by TCP Splice. The duplicated packets are copied into a tap buffer, so the application layer can read data from the tap buffer. We fully utilize the original TCP receive queue as the tap buffer and allow application layer to read data as usual. We chose Linux as the platform for experiment. The TCP Splice and Tap are implemented as Linux modules. Finally, we develop an HTTP proxy to test and verify our implementation. It is shown that the performance of proxy in terms of lower forwarding delay, higher throughput, and increased CPU utilization, can be improved significantly.

BSD Socket API for Simulator is a project to run untouched Real World Application (RWA) binaries on the powerful modern general-purpose network simulators. BSD Socket API for Simulator is designed to eliminate most of the drawbacks of previous works. It is simulator independence, so it can make use of the powerful functionality and versatile tools provided by modern general-purpose simulators such as NS-2. It is fully compatible with BSD Socket API, so RWA can be run on it without re-linking and re-compiling. It is transparent to the RWA, so RWAs are run on BSD Socket API for Simulator as they are on normal operating systems. BSD Socket API for Simulator is built on the concept of message redirecting. It has two critical parts: shared library and customized simulator application. The shared library is loaded into the address space of RWA. On one hand, messages sent by RWA are captured by the shared library and redirected to the customized simulator application. On the other hand, messages from simulator are redirected by the customized simulator application to the shared library. BSD Socket API for Simulator has been intensively tested. The test results show that it functions as expected and it has an acceptable performance.