Optimizing UDP-based Protocol Implementations

Abstract

Because of the poor performance of standard TCP over long distance high-speed networks and the practical difficulty in deploying kernel TCP variants, UDP-based transport protocols are often used for bulk data transfer. However, writing a transport protocol from scratch is not an easy job. One particular difficulty is achieving efficiency in the application level implementation. This paper analyzes the performance characteristics of UDP and describes some optimization techniques that may be useful in most UDP-based protocol implementations, including memory processing, acknowledgment, loss processing, timing and self-clocking, and UDP IO. Based on these optimization principles, we implemented an open protocol framework (Composable UDT) that uses callbacks to process user defined event handlers. This framework can save significant time for network researchers and developers.