Analysis of a single-wavelength optical buffer

Abstract

Abstract-We present a detailed analysis of the loss performance in an optical buffer having access to a single outgoing channel. Such a system -consisting of a number of fiber delay lines -differs significantly from a conventional electronic buffer, in that only a discrete set of delays can be realized for contention resolution.This leads to an underutilization of the channel capacity, which reduces overall performance.Our analysis does not require any special assumptions about the burst-or packet-size distribution, which allows us to study the impact this distribution has on performance. For the important special case of fixed-sized bursts, it reveals, amongst others, that matching fiber delay line length with burst duration is not necessarily the optimal solution in terms of loss performance. It further reveals that, in general, this optimal solution is function not only of burst-size characteristics, but of the offered load as well, making the buffer design process a delicate task.

Blocking and Delay Analysis of Single Wavelength Optical Buffer With General Packet Size Distribution

“…Under the assumptions of Poisson arrivals and independent packet length distribution, in [5], [10], [11] the duration of void period is considered to be uniformly distributed over the interval with mean . Recall that the optical buffer shown in Fig.…”

“…This problem is equivalent to the analytical analysis of an queue with bounded waiting time , where the can be infinite and which makes it infeasible to get a steady state equation like (6) and thus an analytical result on its distribution. That is why the widely adopted approach now is to get the distribution of the above finite queue through analyzing its corresponding infinite queue counterpart without waiting time limit [17]- [20], which results in the offered load constraint of (11) for the stability guarantee of the infinite queue.…”

“…An iterative scheme to approximate optical buffer blocking performance is proposed in [10], which assumes that the packet arrival process is Poisson and the packet length is exponentially distributed. This exponential assumption is relaxed in [11], in which an approximation of blocking probability is obtained and the impact of burst distribution on buffer performance is evaluated. A Markovian model to evaluate the buffer performance numerically under arbitrary traffic patterns is presented in [12].…”

A Hessenberg Markov Chain for Fast Fibre Delay Line Length Optimization

“…Unlike conventional electronic buffers, however, it cannot delay bursts for an arbitrary period of time, but it can only realize a discrete set of N delay values. In [9,2] it is shown that this leads to voids on the outgoing channel. We do not attempt to fill these voids (as this would alter the order of the bursts).…”

“…Several architectures that make use of an FDL buffer have already been identified [3], [4], [8]. The main performance measure of an FDL buffer is its loss rate and analytic and simulation based results concerning the loss rates have been reported in [2], [5], [6], [9], [10], [12].…”