QoS Mapping Along the Protocol Stack: Discussion and Preliminary Results

Quality of service (QoS) mechanisms are needed in integrated networks so that the performance requirements of heterogeneous applications are met. In this paper, we outline a framework for predicting end-to-end QoS at the application layer based on mapping of QoS guarantees across layers in the protocol stack and concatenation of guarantees across multiple dissimilar sub-networks. Mapping is needed to translate QoS guarantees provided in the lower layers into their effects on upper-layer performance indicators. We illustrate the process with some preliminary results for QoS mapping due to segmentation of packets; we conduct a worst-case analysis, generating a closed-form mapping of delay and losses between two layers. Future extensions of this work will take into account flow aggregation processes and the combination of quantitative and qualitative guarantees.