In-service monitoring techniques for cell transfer delay and cell delay variation in ATM networks

Abstract

Cell transfer delay (CTD) and Cell delay variation (CDV) are ATM performance parameters. Monitoring CTD and CDV requires procedures for in-service measurement or estimation and for gaining the delay distribution statistics. This paper discusses the origin and definition of CTD and CDV, the latter being defined in terms of 2-point CDV and l-point CDV. It outlines fundamental measurement techniques based on operation and maintenance (OAM) performance monitoring functions. Also, methods for estimating CTD and 2-point CDV are presented, which do not rely on the availability of synchronized clocks at the measurement points. They are based on a least-square regression analysis which estimates the time and frequency offset of the remote clock.