Through an intensive experimental study, the characteristics of cell delay variation (CDV) and CTD in an ATM network transporting constant bit rate (CBR) traffic under diverse operating conditions are evaluated. We examine the effect of changing network parameters, such as the number of nodes and background load conditions, on the performance parameters of both CDV and CTD. Our results revealed the distributions of CTD and CDV could not be fit to any of the standard distributions (normal, gamma, etc.). The results also present, the autocorrelation behavior of CTD as a function of both load and number of travelled hops. A verification study of the square root law (SRL) of the ATM Forum, on estimating the CTD standard deviation with increasing number of network nodes is also presented. Our results indicate that the SRL reveal very close estimates only under the assumption of a uniform load conditions across all nodes in the network.