protocols developed by private organizations to operate on any vendor hardware
protocols developed by organizations who have control over their definition and operation
protocols that can be freely used by any organization or vendor
Examples of
proprietary protocols are AppleTalk and Novell Netware, which are legacy protocol suites. It is not uncommon for a vendor (or group of vendors)
to develop a proprietary protocol to meet the needs of its customers and later assist in making that proprietary protocol an open standard.