Chapter 6: Communication

Overview

In the past decade , connectivity between computers has become ubiquitous. Ten years ago most personal computers were not attached to a network. In fact, the idea of communicating to another computer typically meant that the user initiated a dial-up connection to a bulletin board system (BBS), and that user s personal computer pretended to be a dumb terminal, simply displaying information from the remote system. As Internet usage grew, users became used to connecting ”again, typically via a dial-up connection ”to the Internet. The computer pretended to be a not-quite-so-dumb terminal that served as a Web browser and displayed rich media content: text, graphics, animations, and eventually video.

As network and Internet connectivity became ubiquitous, developers started producing applications that expected and, in fact, required such connectivity. Some examples are application such as Microsoft Windows Messenger, numerous e-mail clients , newsgroup readers, peer-to-peer applications, and many more. It s not uncommon today for normal desktop applications that don t actually need a network connection to use a connection when present to notify the user when a new version of the application is available.

Unfortunately, developing an application that communicates with other applications has traditionally been rather difficult. The developer of a communicating application needs to deal with numerous difficulties: firewalls, address boundaries, routing issues, authentication and authorization, data security, differing protocols, differing data representations, and more. Longhorn s communication services generally handle all these difficulties for you, allowing you to focus on developing your custom application functionality.