Computer networks have become a vital tool in the daily operations of businesses around the world. For
example, employees in an accounting department can use a common database to access and share
customer account information using DECnet. Using an AppleTalk network, Macintosh users in a
marketing department can share product bulletins, data sheets, and slide presentations. In an engineering
department, Sun workstation users can share product specifications using TCP/IP over Ethernet. And in a
company's manufacturing department, IBM devices attached to a Token Ring network can process
real-time data about material availability and fill orders sent over links from remote offices....