Effects on response time performance using an edge-to-edge protocol in an X.25 packet network

Results presented in earlier work (IEEE J. Sel. Areas Commun. vol.6, no.1, p.190-6, 1988) in which an edge-to-edge protocol was supported between network gateways are reviewed and extended. Emphasis was placed on studying effects of varying the protocol, and, in particular, varying the acknowledgement methods used in window flow-control. The results were obtained with a simulation of a small packet network in which the full X.25 LAPB link protocol was coded in detail on every link in the network. The simulation stepped through each link in half-millisecond time increments, using a Monte Carlo technique to generate data from users and noise on the links. For the current study, an edge-to-edge protocol has been implemented separately for every virtual circuit in the network. Results of the simulation for a three-switch network are presented. The primary measure of performance is the user-perceived round-trip response time from the start of input of a message to completion of a reply from the message destination.<>