DECnet
DECnet Phase V is a superset of the OSI protocol suite and supports all OSI protocols as well as several other proprietary and standard protocols that were supported in previous versions of DECnet. As with past changes to the protocol, DECnet Phase V is compatible with the previous releases (i.e. Phase IV).
Digital Equipment Corporation designed the DECnet stack of protocols in the 1970s as part of its Digital Network Architecture (DNA).