The last few years have witnessed the intensive growth of computer communication networks. The need for nationwide and multination computer communication systems brought about the development of packet-switching networks such as the ARPANET. In this paper we examine a model for computer-to-computer communication via a satellite link. In each network, a single node, the satellite communication concentrator (SCC), manages the flow of information between the terminals in the network and the satellite link. The SCC buffers messages from the terminals and retransmits them over the satellite channel. Buffer space claimed by a message is made free only after the SCC receives an acknowledgment from the receiving network; transmission errors cause the buffer to retransmit the message. The statistical behavior of such a system is considered. Copyright © 1977 by The Institute of Electrical and Electronics Engineers, Inc.