Networks are often characterized by the way they are funded. Private networks are owned and managed by private corporations. For example, many of the major pharmaceutical corporations have internal bioinformatics R&D groups that manage workflow and data with the help of privately owned and highly secure networks. These private networks may be completely isolated, connect to the Internet through a secure firewall, or communicate with academic and commercial collaborators through dedicated, secure lines. Private networks may also be open to researchers and other companiesfor a fee.
In contrast, public networks such as the Internet and the public telephone network are at least partially funded by public coffers. They are also freely open to anyone who is capable of paying for their services. Cooperative networks are supported and managed by their users. One of the best-known cooperative networks was BITNET (Because It's Time Network), started by universities in the early 1980s. Before it was replaced by NSFNET (National Science Foundation Network) in the early 1990s, it connected about 3,000 mainframe computers at universities in the U.S., Canada, South America, Europe, Asia, and Australia.