Patterns in Network Architecture

Chapter 4. Stalking the Upper-Layer Architecture

You have Telnet and FTP. What else do you need?

—Alex McKenzie, 1975

If the Virtual Terminal is in the presentation layer, where is the power supply?

—Al Reska, 1979

Introduction

Although there has been a strong interest in “the upper layers” over the years, as these quotes indicate, there have been differing misconceptions about them. Since the earliest days of the Net, the upper layers have been a bit mysterious and unclear. The early network software removed concerns of reliability and routing from the applications. And with only a couple of dozen hosts connected by what seemed high-speed lines, one had the illusion of having an environment for distributed computing. All of this sparked the ...