Chaosnet is a network protocol that was created at MIT for the LispMachine, and supported by several other OperatingSystems like the IncompatibleTimesharingSystem, TOPS-20, Unix and VAX/VMS. It's a local-area network with no central authority; much faster than the ArpaNet.
Chaosnet defines both a transport layer and application layer--the original Chaosnet spec also defined its own hardware link layer, but later implementations settled on Ethernet as the standard. In modern times it can also be encapsulated through UDP, TLS and Unix sockets. TOPS-20 also implemented IP encapsulation. Chaos-over-Ethernet uses ARP in the standard manner to find hardware links--the original RFC 826 for ARP actually suggests Chaos as an expected protocol for use1.
Unlike TCP, Chaos does not use port numbers to identify services; it uses strings. It is also much easier to develop applications for. Most protocols also have little concept of ComputerSecurity; it was developed in the 70's, after all. It sure as hell isn't encrypted. In this way, Chaosnet may be considered the RightThing.