A ring computer network system having a communication controller for controlling the receipt and sending of packets or messages at each client computer. The interface associated with each client computer includes a send message buffer and a receive message buffer. The send message buffer has a send message buffer counter which increments upwardly is response to messages being received from the client computer for sending on the ring network. The communication controller sends messages from the send buffer until the send message buffer counter reaches the address or a value associated with the last received message. Similarly, the receive message buffer includes a receive message buffer counter which increments as each message is received to a receive message buffer counter value. The receive message buffer is emptied until the receive message buffer counter value is reached. The receive buffer can also have a foreground portion and a background portion. The send buffer can also have a background portion and a foreground portion of memory. The communication controller continually switches between the foreground and background portions of memory and redesignates each memory portion after the switch. The communications controller can also recognize priority schemes for the messages.