Delay Analysis of a Multi-Hop Strict Priority Scheduler

Abstract

Strict priority schedulers are often used in IP networks to guarantee delays for traffic that has strict delay requirements. There is literature for single node bounds for some priorities, however, for end-to-end delay bounds through-traffic is often ignored, which can be crucial in obtaining correct end-to-end bounds. In this paper we give an upper bound on the end-to-end delay and delay variation distributions for all the priorities in a strict priority scheduler. We assume the highest two priorities are aggregates of constant-bit rate traffic, the third priority is modeled as an aggregate of on-off sources (e.g., VoIP), followed by a video stream. The delay distribution takes through-traffic and cross-traffic into account. Using simulations we demonstrate that our approach gives an upper bound to the delay and delay variation distributions.