Performance modeling of partial packet discarding using the end-of-packet indicator in AAL type 5

The ATM adaptation layer type 5 (AAL5) is an adaptation layer protocol for the ATM layer of broadband integrated services digital networks (BISDNs), which targets connection-oriented services. Among several features, it is unique in the sense that it includes an end-of-packet (EOP) indicator in the header of the ATM cell (the ATM-layer-user-to-ATM-layer-user (AUU) parameter in the payload type (PT) field). It was suggested that the use of this indicator may be used to provide a means by which buffer occupancy can be reduced by selectively dropping cells from already incomplete packets [Armitage and Adams, 1993]. The objective of this paper is to study the performance of this layer and the effectiveness of the EOP indicator. The performance measures of interest are the probability of packet loss and the mean packet delay. An approximate analytical model is constructed in which the blocking of a tagged source is kept track of in an exact manner. The rest of the sources are modeled approximately. The accuracy of the model is enhanced through an iterative approach. A simulation model is also constructed to assess the accuracy of the approximate model.