As corporations began to employ tens, then hundreds, finally thousands, of CPUs in their various offices, they wanted them to communicate in some faster fashion than "sneakernet," a facetious name for the transportation of tapes or diskettes across machine rooms or through the mail. Using the modem, these corporations asked vendors to develop complete networking solutions for them, and many of the large vendors did, such as IBM with their SNA (Systems Network Architecture) and DEC with their DNA (Digital Network Architecture).

All of these proprietary systems were flawed in that they didn't allow communication between computers of different vendors. But back in the 1960s, nobody thought that someday almost all computers would be connected. Nobody but the military, that is.