ABSTRACT
Packet data communication progresses in a sequence of stages. Each stage consists of a subset of the following steps: arrive, wait, process, forward, and travel a physical distance. From the point of view of evaluation of the overall performance, each such stage is a queuing system. This is the case, for example, in a network wherein a data frame over a long distance link starts to appear at the input of a system. In many such systems, arrivals can take place at arbitrary time instants so that interarrival times (IATs) are considered to be real variables as opposed to discrete variables. It is common for a data packet to be referred to as a data frame in the datalink layer of the data communication protocol hierarchy.
