Amazon.com description: Product Description: The primary objective of this volume is the exploration of important topics in the area of the "upper layers", that is, networking functions beyond information control. Contributions, made by leading experts from around the world, discuss aspects ranging from application layer development environments and presentation layer issues, through services including electronic mail and directories, to group communication, protocols and architectural considerations. In identifying new research directions, it is hoped the book will stimulate scientists, engineers and students in the future development of this area of computer and communications technology.