Real-time block transfer under a link-sharing hierarchy

Most application data units are too large to be carried in a single packet (or cell) and must be segmented for network delivery. To an application, the end-to-end delays and loss rate of its data units are much more relevant performance measures than ones specified for individual packets (or cells). The concept of a burst (or block) was introduced to represent a sequence of packets (or cells) that carry an application data unit. We describe how a real-time variable bit-rate (VBR) service, with quality of service (QoS) parameters for block transfer delay and block loss rate, can be provided by integrating concepts and delay guarantee results from our previous work on burst scheduling, together with ideas from asynchronous transfer mode (ATM) block transfer. Two new contributions are presented herein. First, we design an admission control algorithm to provide the following two classes of service: bounded-delay block transfer with no loss, and bounded-delay block transfer at a specified block loss rate. Secondly, we show how to extend existing end-to-end delay bounds to networks with hierarchical link sharing.