Chaosnet

Chaosnet was the name for both an internetworking protocol family, and an early LAN technology, both invented at the MIT AI Laboratory; the latter was the LAN on which the protocol first ran.

The LAN was a CSMA-CD system modeled on the Xerox PARC 3 megabit/second Experimental Ethernet, running over cable TV coaxial cable (using standard CATV connectors to connect the transceivers; not vampire taps, as on the Experimental Ethernet).

The protocol was later made to run over standard 10 megabit/second Ethernet, which largely supplanted the Chaosnet hardware. (On Ethernet, the Address Resolution Protocol is required to provide mappings from 16-bit Chaos addresses to the 48-bit addresses used by Ethernet.)

The protocol provided a reliable byte stream service, but also had a datagram mode.

History

Chaosnet was initially called CAIOSnet.

Implementations

• LISP machines
• ITS
• TOPS-20
• FOONEX
• VAX/VMS
• BSD Unix
• MINITS
• PDP-11 Unix V7
• Unix V8
• MagicSix
• Chaosnet Bridge
• Oswalds's Python and Lisp implementations
• Linux

Hardware, and simulations

• CH11, UNIBUS device
• QBCHNI, QBUS device
• CH10, PDP-10 I/O bus device

• KLH10 simulates a CH11
• SIMH's KS10, PDP-11, and VAX simulate a CH11
• SIMH's KA10 and KL10 simulates a CH10

External links

• AI memo 628 - Includes chapters on ITS, TOPS-20, Lisp Machine, and Unix implementations.
• SYSDOC;CHAORD > - Initial design
• MOON;AMBER > - Another Moon document
• Chaosnet - Detailed descriptions of both the hardware system, and the protociol(s)
• CHAOS; - hardware interface designs, etc.
  • CHAOS;CHAOS PLANS - interesting details of the physical installation at MIT