Mapping of Loss and Delay Between IP and ATM Using Network Calculus

End-to-end QoS requires accurate mapping of QoS classes and particularly QoS parameters between the different, heterogeneous layers and protocols present at the terminal equipment and intermediate nodes. In the IP over ATM context, both technologies offer QoS capabilities but differ in architecture, service classes and performance parameters. In this paper, we consider mapping of loss and delay between Integrated Services IP and ATM, using Network Calculus (NC), a min-plus algebra formulation. NC targets lossless systems only and is thus suitable for guaranteed services. However, as our aim is to quantify and map loss and delay in the presence of loss, we extend the theory so as to account for lossy systems too, as shall be the case for nonconformant traffic and congested systems. Loss is introduced by setting constraints on both the delay and the buffer size at the network elements. Numerical applications are used to further illustrate the mapping of loss and delay between IP and ATM.