A networking system may include one or more network nodes such as one or more network switches. The network switches include respective matching engines. The matching engines across the network switches may be configured to match on a consistent set of matching criteria based on low and high entropy data fields to sample a same subset of packets for each network flow of interest. The sampled packets may include annotations and may be sent to collector circuitry for analysis. Controller circuitry may enforce consistent sampling policies across the network switches.