The Cambridge Ring was an experimental local area network architecture developed at the Computer Laboratory, University of Cambridge starting in 1974 and continuing into the 1980s. It was a ring network with a theoretical limit of 255 nodes (though such a large number would have badly affected performance), around which cycled a fixed number of packets. Free packets would be "loaded" with data by a machine wishing to send, marked as received by the destination machine, and "unloaded" on return to the sender; thus in principle there could be as many simultaneous senders as packets. The network ran over twin twisted-pair cabling (plus a fibre-optic section).
People associated with the project include Andy Hopper, David Wheeler, Maurice Wilkes, and Roger Needham.
In 2002 the Cambridge University Computer Laboratory launched a graduate society called the Cambridge Computer Lab Ring named after the Cambridge Ring.