Chaosnet is a local area network technology. It was first developed by Thomas Knight and Jack Holloway at MIT's AI Lab in 1975 and thereafter. It refers to two separate, but closely related, technologies. The more widespread was a set of computer communication packet-based protocols intended to connect the then-recently developed and very popular (within MIT) Lisp machines; the second was one of the earliest local area network (LAN) hardware implementations.
The Chaosnet protocol originally used an implementation over CATV coaxial cable modeled on the early Xerox PARC 3 megabit/second Ethernet, the early ARPANET, and Transmission Control Protocol (TCP). It was a contention-based system intended to work over a 0–1000 meter range, that included a pseudo-slotted feature intended to reduce collisions, which worked by passing a virtual token of permission from host to host; successful packet transmissions updated each host's knowledge of which host had the token at that time. Collisions caused a host to fall silent for a duration depending on the distance from the host it collided with. Collisions were never a real problem, and the pseudo-slotting fell into disuse.
Chaosnet's network topology was usually series of linear (not circular) cables, each up to a maximum of a kilometer and roughly 12 clients. The individual segments were interconnected by "bridges" (much in the ARPANET mold), generally older computers like PDP-11s with two network interfaces.