Client/server design for fast retrieval of large images on the Internet

At the National Library of Medicine (NLM), an application-level technique for improving the transmission rate of large images across the Internet has been developed. Initial performance tests were conducted in 1994 and evaluation has continued with a series of tests conducted with cervical X-ray image files transmitted from Texas Tech University, the University of Arizona and the NASA Lewis Research Center to NLM. Statistics were collected to compare the observed transmission rate using the NLM technique versus conventional FTP transmission. On the links tested, the average transmission rate using the new technique showed a consistent improvement over conventional methods, including a 2- to 3-fold improvement on the Tucson and Cleveland tests. Work is now underway to extend the initial implementation into a portable, robust technique. In this paper, we present high-level design concepts for the second implementation and provide results of the most recent tests