An introductory article covers SS7 protocol, services, reliability, performance, and congestion control. Following the introductory article, the papers are arranged in three sections. The largest section is on performance analysis and congestion control. The papers in the second section address several issues relevant to the network level, including the impact of new services. The last section of this issue contains papers that highlight technical issues for future studies. This section carries a dual purpose: to introduce the preliminary results achieved by the authors and to suggest directions for additional work in this area.>

The authors wish to provide a unification of this issue's papers by providing a clear context for them. Common channel signaling can be defined as the system that enables stored program control exchanges, network databases, and other nodes of a network to exchange messages related to call setup, supervision, and take down (call and connection control information); information needed for distributed application processing (interprocess query and response or user-to-user data); and network management information.>

A multipoint private line (MPL) network is designed to operate within specified system-performance objectives. Performance objectives for some types of computer-communications networks are stated in terms of access-delay statistics which measure the grade of service experienced by the stations bidding for access to the private line. Access delay is defined to be the time from when a message reaches the head of its queue at the station-and no message from its queue is being processed-until transmission of the message begins. Using simulation and some analysis, we examine and compare the access delay statistics for an MPL circuit under each of four possible service disciplines for the stations on the circuit. The results in this paper have proven useful in designing certain types of MPL networks for a variety of system parameters.

It is anticipated that computer-communications systems designed for the purpose of transmitting data from geographically clustered terminals to a remote computer will employ multiplexing techniques in order to reduce transmission costs. A procedure is described for determining, under three criteria, the optimum computer buffer size assuming that the data traffic arriving at the multiplexer is Poisson and that the multiplexer and data link (transmission line) can, together, be represented by a constant-holding-time server. The approach taken is that since the computer is in tandem with the multiplexer and data link, we can make use of analytical results on the output process of an M/D/1 queueing system (the multiplexer and data link) in order to design the computer buffer. A comparison is made between the proposed procedure, the "worst case" designs, and other possible analytical approaches to the problem.