Can confidence intervals be applied to flow-export data (and cflowd analyses) for billing applications?
You can calculate a rough confidence interval from flow-export data, since it contains sequence numbers. The root of the problem with the sequence numbers today is that they don’t tell you the significance of the flow data you missed. They could have been big flows (a lot of packets and bytes), the flow-export sequence number doesn’t tell you. In most cases, you should just make sure you’re not missing a significant number of flows. Off the cuff, I’d guess that there is probably an inverse relationship between the number of dropped flows and the amount of traffic per flow (many small flows cause higher flow-export rates, and congestion is the leading cause of dropped flow-export packets). A more conservative approach would assume a gaussian distribution about the average of the flows you have received. In either case, it’s probably a manageable error if (and only if) you’re not missing a lot of the data. The bigger problem is the granularity of data necessary to do very granular billin
