There exists a class of systems with requirements for real-time data delivery, limits on end-to-end delay, and limits on jitter. These systems can have components distributed across a wide area. In addition, the components distributed across a wide area require that the arrival and departure of data occur synchronously. To support these classes of systems, the communication systems must be able to transmit the required information within a pre-determined window of time. Due to the synchronous nature and requirements of these classes of systems, they are referred to as being Synchronous Dependent (SD). This research models and characterizes a serial communication link for application in a strict time constraint environment. These applications will also have limitations on jitter and delay, relative to the need to synchronize with other components of the system. Additionally, the research provides the modeling of users that utilize applications with relaxed constraints. The communication link will be able to support multiple users with varying requirements, from highly periodic control data to aperiodic general data. The network link is a modified T-channel, with resource reservation applying to both bandwidth and size allocation of a data frame. In contrast to a standard T-channel, the link has adjustable channel sizes, as well as the capability to shift a transmission out of the assigned channel into a channel either earlier or later than the previously assigned channel. In addition, a user may use more than one consecutive channel for the transmission of a single instance of information, i.e., multiple channels can be viewed as concatenated for use by a single user. The purpose of the channel is to provide a dedicated time slot available to the user that needs to transmit at a specific time that is also periodic. Through the modeling of the user's communications across the link, it is possible to examine the potential effects of the various characteristics of the individual user on the other users requesting access to the link. Assuming no adverse affects and to insure that time sensitive data are delivered on time, a method to determine the acceptability of the admission of the given user has been designed to determine which users will have access to the link and those that will not
