This paper addresses the problem of estimating the worst-case end-to-end delay for a flow in a tandem of FIFO multiplexing nodes, following up our previous work [12]. We show that, contrary to the expectations, the state-of-the-art method for computing delay bounds, i.e. upper bounds on the worst-case delay, called the Least Upper Delay Bound (LUDB) methodology, may actually be larger than the worst-case delay even in simple cases. Thus, we first devise a method to compute improved delay bounds. Then, in order to assess how close the derived bounds are to the actual, still unknown, worst-case delays, we devise a method to compute lower bounds on the worst-case delay. Our analysis shows that the gap between the upper and lower bounds is quite small in many practical cases, which implicitly validates the upper bounds themselves.
Estimating the Worst-case Delay in FIFO Tandems Using Network Calculus
LENZINI, LUCIANO;MINGOZZI, ENZO;STEA, GIOVANNI
2008-01-01
Abstract
This paper addresses the problem of estimating the worst-case end-to-end delay for a flow in a tandem of FIFO multiplexing nodes, following up our previous work [12]. We show that, contrary to the expectations, the state-of-the-art method for computing delay bounds, i.e. upper bounds on the worst-case delay, called the Least Upper Delay Bound (LUDB) methodology, may actually be larger than the worst-case delay even in simple cases. Thus, we first devise a method to compute improved delay bounds. Then, in order to assess how close the derived bounds are to the actual, still unknown, worst-case delays, we devise a method to compute lower bounds on the worst-case delay. Our analysis shows that the gap between the upper and lower bounds is quite small in many practical cases, which implicitly validates the upper bounds themselves.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
