a technique for establishing and maintaining full duplex communication between two stations connected to a token ring network , without physically reconfiguring the station connections or otherwise disturbing the network . in an auto - configuration full duplex mode of operation , each station ascertains whether there are only two active stations on the network and , if so , performs an exchange of frames with the other station to establish full duplex communication . one way to ascertain whether only two stations are active is for each station to transmit periodically a neighbor information frame , which contains the indentities of the source station and the source station &# 39 ; s nearest upstream neighbor . once established , full duplex communication can proceed at a greater bandwidth than communication in a token ring network , and without latency delays and distance limitations associated with token ring networks . periodic checks are made by each station in full duplex communication , to ascertain if the other station is still participating or if any third station has become active . in either case , stations in the auto - configuration mode revert to token ring mode automatically . in a variant form of the invention , stations can operate in a fixed full duplex mode , in which the detection of tokens or third stations are merely reported and do not necessarily result in reversion to the token ring mode .