Chapter 1. Introduction to Bonjour and Zeroconf

You walk in a few minutes late to a meeting and want to know what you've missed. You open your text editor and your computer automatically discovers a shared document in which one or more attendees are taking notes. You have a couple of colleagues who are busy in another meeting but are interested in the topics being discussed in your meeting. You invite your colleagues to view the notes being taken and to contribute their comments and questions. A presenter announces that anyone wanting a copy of his slides should let him know. You open your local Instant Messenger application and see his name in the list of available names, even though you have never met before and he is not in your buddy list. A moment later, he has placed his presentation in your drop box in your Public folder, which he has discovered in his network directory.

The meeting comes to an end. Before anyone erases the whiteboard, someone snaps a quick picture or two and puts it in their photo-sharing library so that anyone interested can download it. You notice a new entry in your audio software that announces that the person who was recording the session has already posted it in her shared audio library. Before you save the notes on the session, you decide to print out a copy to read on the plane ride back. In the print dialog, you discover several printers and choose the one labeled "Third Floor Meeting Rooms."

This is not a fantastical glimpse of the elusive future. It is a concrete description of what is available today using Zeroconf. In this chapter, you will get a quick overview of the various components that make up Zeroconf. In the following four chapters, these details will be fleshed out. The second half of this chapter examines the Zeroconf design principles that build on two decades of experience with the AppleTalk Name Binding Protocol.