Hi, I am using the ns-lan.tcl init-monitor, sample-queue-size...etc. I had the following problems: 1) when the [new BytesIntegrator] was initiated, it would not resolve and would be as unkown command, is it suppose to be Integrator. 2) Same for PktsIntegrator 3) I made both changes to Integrator and did get NEGATIVE numbers for the mean bytes and pkts. Any help is appreciated. Thanks, Emad.